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Posted to issues@maven.apache.org by GitBox <gi...@apache.org> on 2020/05/27 03:42:13 UTC

[GitHub] [maven-dependency-plugin] jonvolfson opened a new pull request #57: Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

jonvolfson opened a new pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57


   @elharo @bimargulies 
   


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[GitHub] [maven-dependency-plugin] elharo commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

elharo commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r431398044



##########
File path: src/test/java/org/apache/maven/plugins/dependency/TestGetClassesMojo.java
##########
@@ -0,0 +1,86 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.LegacySupport;
+import org.apache.maven.plugin.testing.stubs.MavenProjectStub;
+import org.apache.maven.settings.Server;
+import org.apache.maven.settings.Settings;
+import org.sonatype.aether.impl.internal.SimpleLocalRepositoryManager;

Review comment:
       Not off the top of my head but try calling `lookup(LocalRepositoryManager.class)` in the setUp method and see if that returns an object that works. 




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[GitHub] [maven-dependency-plugin] jonvolfson commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r441031441



##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;

Review comment:
       fixed




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[GitHub] [maven-dependency-plugin] jonvolfson commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r431277013



##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    private void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration entries = jarFile.entries();
+
+        while ( entries.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) entries.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( !name.endsWith( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );
+        }
+        jarFile.close();
+    }
+
+    private ProjectBuildingRequest buildBuildingRequest()
+            throws MojoExecutionException, MojoFailureException
+    {
+        if ( artifact == null )
+        {
+            throw new MojoFailureException( "You must specify an artifact, "
+                    + "e.g. -Dartifact=org.apache.maven.plugins:maven-downloader-plugin:1.0" );
+        }
+        if ( artifact != null )
+        {
+            String[] tokens = artifact.split( ":" );
+            if ( tokens.length < 3 || tokens.length > 5 )
+            {
+                throw new MojoFailureException( "Invalid artifact, you must specify "
+                        + "groupId:artifactId:version[:packaging[:classifier]] " + artifact );
+            }
+            coordinate.setGroupId( tokens[0] );
+            coordinate.setArtifactId( tokens[1] );
+            coordinate.setVersion( tokens[2] );
+            if ( tokens.length >= 4 )
+            {
+                coordinate.setType( tokens[3] );
+            }
+            if ( tokens.length == 5 )
+            {
+                coordinate.setClassifier( tokens[4] );
+            }
+        }
+
+        ArtifactRepositoryPolicy always =
+                new ArtifactRepositoryPolicy( true, ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
+                        ArtifactRepositoryPolicy.CHECKSUM_POLICY_WARN );
+
+        List<ArtifactRepository> repoList = new ArrayList<>();
+
+        if ( pomRemoteRepositories != null )
+        {
+            repoList.addAll( pomRemoteRepositories );
+        }
+
+        if ( remoteRepositories != null )
+        {
+            // Use the same format as in the deploy plugin id::layout::url
+            String[] repos = remoteRepositories.split( "," );
+            for ( String repo : repos )
+            {
+                repoList.add( parseRepository( repo, always ) );
+            }
+        }
+
+        ProjectBuildingRequest buildingRequest =
+                new DefaultProjectBuildingRequest( session.getProjectBuildingRequest() );
+
+        Settings settings = session.getSettings();
+        repositorySystem.injectMirror( repoList, settings.getMirrors() );
+        repositorySystem.injectProxy( repoList, settings.getProxies() );
+        repositorySystem.injectAuthentication( repoList, settings.getServers() );
+
+        buildingRequest.setRemoteRepositories( repoList );
+
+        return buildingRequest;
+    }
+
+    protected ArtifactCoordinate toArtifactCoordinate( DependableCoordinate dependableCoordinate )
+    {
+        ArtifactHandler artifactHandler = artifactHandlerManager.getArtifactHandler( dependableCoordinate.getType() );
+        DefaultArtifactCoordinate artifactCoordinate = new DefaultArtifactCoordinate();
+        artifactCoordinate.setGroupId( dependableCoordinate.getGroupId() );
+        artifactCoordinate.setArtifactId( dependableCoordinate.getArtifactId() );
+        artifactCoordinate.setVersion( dependableCoordinate.getVersion() );
+        artifactCoordinate.setClassifier( dependableCoordinate.getClassifier() );
+        artifactCoordinate.setExtension( artifactHandler.getExtension() );
+        return artifactCoordinate;
+    }
+
+    ArtifactRepository parseRepository( String repo, ArtifactRepositoryPolicy policy )
+            throws MojoFailureException
+    {
+        // if it's a simple url
+        String id = "temp";
+        ArtifactRepositoryLayout layout = getLayout( "default" );
+
+        // if it's an extended repo URL of the form id::layout::url
+        if ( repo.contains( "::" ) )
+        {
+            Matcher matcher = ALT_REPO_SYNTAX_PATTERN.matcher( repo );
+            if ( !matcher.matches() )
+            {
+                throw new MojoFailureException( repo, "Invalid syntax for repository: " + repo,
+                        "Invalid syntax for repository. Use \"id::layout::url\" or \"URL\"." );
+            }
+
+            id = matcher.group( 1 ).trim();
+            if ( !( matcher.group( 2 ) == null || matcher.group( 2 ).trim().isEmpty() ) )
+            {
+                layout = getLayout( matcher.group( 2 ).trim() );
+            }
+            repo = matcher.group( 3 ).trim();
+        }
+        return new MavenArtifactRepository( id, repo, layout, policy, policy );
+    }
+
+    private ArtifactRepositoryLayout getLayout( String id )
+            throws MojoFailureException
+    {
+        ArtifactRepositoryLayout layout = repositoryLayouts.get( id );
+
+        if ( layout == null )
+        {
+            throw new MojoFailureException( id, "Invalid repository layout", "Invalid repository layout: " + id );
+        }
+
+        return layout;
+    }
+
+    /**
+     * @return {@link #skip}
+     */
+    protected boolean isSkip()
+    {
+        return skip;
+    }
+
+    protected boolean isTransitive()
+    {
+        return transitive;
+    }
+
+    protected DefaultDependableCoordinate getCoordinate()
+    {
+        return coordinate;
+    }
+
+    protected DependencyResolver getDependencyResolver()
+    {
+        return dependencyResolver;
+    }
+
+    protected ArtifactResolver getArtifactResolver()
+    {
+        return artifactResolver;
+    }
+
+    /**
+     * @param artifact The artifact.

Review comment:
       fixed

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    private void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration entries = jarFile.entries();
+
+        while ( entries.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) entries.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( !name.endsWith( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );

Review comment:
       fixed

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    private void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration entries = jarFile.entries();
+
+        while ( entries.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) entries.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( !name.endsWith( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );
+        }
+        jarFile.close();
+    }
+
+    private ProjectBuildingRequest buildBuildingRequest()

Review comment:
       fixed

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );

Review comment:
       fixed




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[GitHub] [maven-dependency-plugin] elharo merged pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

elharo merged pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57


   


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[GitHub] [maven-dependency-plugin] rmannibucau commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

rmannibucau commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r430520214



##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,396 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver().resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver().resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();
+
+        while ( e.hasMoreElements() )
+        {
+            JarEntry entry = ( JarEntry )e.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( name.length() <= 6 || !name.substring( name.length() - 6 ).equals( ".class" )) {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );

Review comment:
       +1, can be neat to be able to inject the list of classes in a maven project properties to reuse it downstream (exec-maven-plugin is my immediate thought but i'm sure there are more use cases). A dump in a file can be useful too.
   
   side note: what about multi release jars (META-INF/versions)? should it be filtered?

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,396 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )

Review comment:
       @bimargulies-google I'd keep it since you never know how it is used and maven does not control that




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[GitHub] [maven-dependency-plugin] jonvolfson commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r431278088



##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()

Review comment:
       fixed




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[GitHub] [maven-dependency-plugin] jonvolfson commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r441030053



##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();
+
+        while ( e.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) e.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( name.length() <= 6 || !name.substring( name.length() - 6 ).equals( ".class" ) )

Review comment:
       fixed, forgot to comment




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[GitHub] [maven-dependency-plugin] elharo commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

elharo commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r431312447



##########
File path: src/test/java/org/apache/maven/plugins/dependency/TestGetClassesMojo.java
##########
@@ -0,0 +1,87 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.LegacySupport;
+import org.apache.maven.plugin.testing.stubs.MavenProjectStub;
+import org.apache.maven.settings.Server;
+import org.apache.maven.settings.Settings;
+import org.junit.Assert;
+import org.sonatype.aether.impl.internal.SimpleLocalRepositoryManager;
+import org.sonatype.aether.util.DefaultRepositorySystemSession;
+
+import java.io.File;
+
+public class TestGetClassesMojo
+        extends AbstractDependencyMojoTestCase
+{
+    ListClassesMojo mojo;

Review comment:
       make field private

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,391 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. That is,
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = makeBuildingRequest();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = dependencyResolver
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = artifactResolver
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact " + artifact + ": " + e.getMessage(), e );

Review comment:
       This message might not be quite accurate when you're downloading all transitive dependencies. That is, it could be one of the transitive deps we can't download instead of the original.

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,391 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. That is,
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *

Review comment:
       nit: remove blank line

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,391 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. That is,
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = makeBuildingRequest();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = dependencyResolver
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = artifactResolver
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact " + artifact + ": " + e.getMessage(), e );
+        }
+    }
+
+    private void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration entries = jarFile.entries();
+
+        while ( entries.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) entries.nextElement();
+            String entryName = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( !entryName.endsWith( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            String className = entryName.substring( 0, entryName.length() - 6 ).replace( '/', '.' );
+            getLog().info( className );
+        }
+        jarFile.close();

Review comment:
       use try-with-resources to guarantee that this is closed when an exception is thrown

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,391 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. That is,
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = makeBuildingRequest();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = dependencyResolver
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = artifactResolver
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact " + artifact + ": " + e.getMessage(), e );
+        }
+    }
+
+    private void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration entries = jarFile.entries();
+
+        while ( entries.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) entries.nextElement();
+            String entryName = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( !entryName.endsWith( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            String className = entryName.substring( 0, entryName.length() - 6 ).replace( '/', '.' );
+            getLog().info( className );
+        }
+        jarFile.close();
+    }
+
+    private ProjectBuildingRequest makeBuildingRequest()
+            throws MojoExecutionException, MojoFailureException
+    {
+        if ( artifact == null )
+        {
+            throw new MojoFailureException( "You must specify an artifact, "
+                    + "e.g. -Dartifact=org.apache.maven.plugins:maven-downloader-plugin:1.0" );
+        }
+        if ( artifact != null )
+        {
+            String[] tokens = artifact.split( ":" );
+            if ( tokens.length < 3 || tokens.length > 5 )
+            {
+                throw new MojoFailureException( "Invalid artifact, you must specify "
+                        + "groupId:artifactId:version[:packaging[:classifier]] " + artifact );
+            }
+            coordinate.setGroupId( tokens[0] );
+            coordinate.setArtifactId( tokens[1] );
+            coordinate.setVersion( tokens[2] );
+            if ( tokens.length >= 4 )
+            {
+                coordinate.setType( tokens[3] );
+            }
+            if ( tokens.length == 5 )
+            {
+                coordinate.setClassifier( tokens[4] );
+            }
+        }
+
+        ArtifactRepositoryPolicy always =
+                new ArtifactRepositoryPolicy( true, ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
+                        ArtifactRepositoryPolicy.CHECKSUM_POLICY_WARN );
+
+        List<ArtifactRepository> repoList = new ArrayList<>();
+
+        if ( pomRemoteRepositories != null )
+        {
+            repoList.addAll( pomRemoteRepositories );
+        }
+
+        if ( remoteRepositories != null )
+        {
+            // Use the same format as in the deploy plugin id::layout::url
+            String[] repos = remoteRepositories.split( "," );
+            for ( String repo : repos )
+            {
+                repoList.add( parseRepository( repo, always ) );
+            }
+        }
+
+        ProjectBuildingRequest buildingRequest =
+                new DefaultProjectBuildingRequest( session.getProjectBuildingRequest() );
+
+        Settings settings = session.getSettings();
+        repositorySystem.injectMirror( repoList, settings.getMirrors() );
+        repositorySystem.injectProxy( repoList, settings.getProxies() );
+        repositorySystem.injectAuthentication( repoList, settings.getServers() );
+
+        buildingRequest.setRemoteRepositories( repoList );
+
+        return buildingRequest;
+    }
+
+    protected ArtifactCoordinate toArtifactCoordinate( DependableCoordinate dependableCoordinate )
+    {
+        ArtifactHandler artifactHandler = artifactHandlerManager.getArtifactHandler( dependableCoordinate.getType() );
+        DefaultArtifactCoordinate artifactCoordinate = new DefaultArtifactCoordinate();
+        artifactCoordinate.setGroupId( dependableCoordinate.getGroupId() );
+        artifactCoordinate.setArtifactId( dependableCoordinate.getArtifactId() );
+        artifactCoordinate.setVersion( dependableCoordinate.getVersion() );
+        artifactCoordinate.setClassifier( dependableCoordinate.getClassifier() );
+        artifactCoordinate.setExtension( artifactHandler.getExtension() );
+        return artifactCoordinate;
+    }
+
+    ArtifactRepository parseRepository( String repo, ArtifactRepositoryPolicy policy )
+            throws MojoFailureException
+    {
+        // if it's a simple url
+        String id = "temp";
+        ArtifactRepositoryLayout layout = getLayout( "default" );
+
+        // if it's an extended repo URL of the form id::layout::url
+        if ( repo.contains( "::" ) )
+        {
+            Matcher matcher = ALT_REPO_SYNTAX_PATTERN.matcher( repo );
+            if ( !matcher.matches() )
+            {
+                throw new MojoFailureException( repo, "Invalid syntax for repository: " + repo,
+                        "Invalid syntax for repository. Use \"id::layout::url\" or \"URL\"." );
+            }
+
+            id = matcher.group( 1 ).trim();
+            if ( !( matcher.group( 2 ) == null || matcher.group( 2 ).trim().isEmpty() ) )
+            {
+                layout = getLayout( matcher.group( 2 ).trim() );
+            }
+            repo = matcher.group( 3 ).trim();
+        }
+        return new MavenArtifactRepository( id, repo, layout, policy, policy );
+    }
+
+    private ArtifactRepositoryLayout getLayout( String id )
+            throws MojoFailureException
+    {
+        ArtifactRepositoryLayout layout = repositoryLayouts.get( id );
+
+        if ( layout == null )
+        {
+            throw new MojoFailureException( id, "Invalid repository layout", "Invalid repository layout: " + id );
+        }
+
+        return layout;
+    }
+
+    /**
+     * @return {@link #skip}

Review comment:
       I don't think you need these getter methods, and probably not the setters




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[GitHub] [maven-dependency-plugin] jonvolfson commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r441029465



##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7

Review comment:
       fixed, forgot to comment




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[GitHub] [maven-dependency-plugin] elharo commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

elharo commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r430534915



##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.

Review comment:
       class dependencies for --> "classes contained in" as these are not dependencies

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo

Review comment:
       Perhaps ListClassesMojo?

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();
+
+        while ( e.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) e.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( name.length() <= 6 || !name.substring( name.length() - 6 ).equals( ".class" ) )

Review comment:
       name.endsWith(".class")

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.

Review comment:
       group ID

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";

Review comment:
       will this work for anything that's not a jar?

##########
File path: src/test/java/org/apache/maven/plugins/dependency/TestGetClassesMojo.java
##########
@@ -0,0 +1,86 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.LegacySupport;
+import org.apache.maven.plugin.testing.stubs.MavenProjectStub;
+import org.apache.maven.settings.Server;
+import org.apache.maven.settings.Settings;
+import org.sonatype.aether.impl.internal.SimpleLocalRepositoryManager;
+import org.sonatype.aether.util.DefaultRepositorySystemSession;
+
+import java.io.File;
+
+public class TestGetClassesMojo
+        extends AbstractDependencyMojoTestCase
+{
+    GetClassesMojo mojo;

Review comment:
       private

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7

Review comment:
       `@since` doesn't make sense here

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );

Review comment:
       Not a helpful log message. In general we have way too much logging. Only log things the end user actually wants to see.

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )

Review comment:
       why is this public? Methods should have the most restrictive access possible.

##########
File path: src/test/java/org/apache/maven/plugins/dependency/TestGetClassesMojo.java
##########
@@ -0,0 +1,86 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.LegacySupport;
+import org.apache.maven.plugin.testing.stubs.MavenProjectStub;
+import org.apache.maven.settings.Server;
+import org.apache.maven.settings.Settings;
+import org.sonatype.aether.impl.internal.SimpleLocalRepositoryManager;
+import org.sonatype.aether.util.DefaultRepositorySystemSession;
+
+import java.io.File;
+
+public class TestGetClassesMojo
+        extends AbstractDependencyMojoTestCase
+{
+    GetClassesMojo mojo;
+
+    protected void setUp()
+            throws Exception
+    {
+        // required for mojo lookups to work
+        super.setUp( "markers", false );
+
+        File testPom = new File( getBasedir(), "target/test-classes/unit/get-test/plugin-config.xml" );
+        assert testPom.exists();

Review comment:
       NEVER use assert

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();
+
+        while ( e.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) e.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( name.length() <= 6 || !name.substring( name.length() - 6 ).equals( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );
+        }
+        jarFile.close();
+    }
+
+    public ProjectBuildingRequest buildBuildingRequest()
+            throws MojoExecutionException, MojoFailureException
+    {
+        if ( artifact == null )
+        {
+            throw new MojoFailureException( "You must specify an artifact, "
+                    + "e.g. -Dartifact=org.apache.maven.plugins:maven-downloader-plugin:1.0" );
+        }
+        if ( artifact != null )
+        {
+            String[] tokens = StringUtils.split( artifact, ":" );
+            if ( tokens.length < 3 || tokens.length > 5 )
+            {
+                throw new MojoFailureException( "Invalid artifact, you must specify "
+                        + "groupId:artifactId:version[:packaging[:classifier]] " + artifact );
+            }
+            coordinate.setGroupId( tokens[0] );
+            coordinate.setArtifactId( tokens[1] );
+            coordinate.setVersion( tokens[2] );
+            if ( tokens.length >= 4 )
+            {
+                coordinate.setType( tokens[3] );
+            }
+            if ( tokens.length == 5 )
+            {
+                coordinate.setClassifier( tokens[4] );
+            }
+        }
+
+        ArtifactRepositoryPolicy always =
+                new ArtifactRepositoryPolicy( true, ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
+                        ArtifactRepositoryPolicy.CHECKSUM_POLICY_WARN );
+
+        List<ArtifactRepository> repoList = new ArrayList<>();
+
+        if ( pomRemoteRepositories != null )
+        {
+            repoList.addAll( pomRemoteRepositories );
+        }
+
+        if ( remoteRepositories != null )
+        {
+            // Use the same format as in the deploy plugin id::layout::url
+            String[] repos = StringUtils.split( remoteRepositories, "," );
+            for ( String repo : repos )
+            {
+                repoList.add( parseRepository( repo, always ) );
+            }
+        }
+
+        ProjectBuildingRequest buildingRequest =
+                new DefaultProjectBuildingRequest( session.getProjectBuildingRequest() );
+
+        Settings settings = session.getSettings();
+        repositorySystem.injectMirror( repoList, settings.getMirrors() );
+        repositorySystem.injectProxy( repoList, settings.getProxies() );
+        repositorySystem.injectAuthentication( repoList, settings.getServers() );
+
+        buildingRequest.setRemoteRepositories( repoList );
+
+        return buildingRequest;
+    }
+
+    protected ArtifactCoordinate toArtifactCoordinate( DependableCoordinate dependableCoordinate )
+    {
+        ArtifactHandler artifactHandler = artifactHandlerManager.getArtifactHandler( dependableCoordinate.getType() );
+        DefaultArtifactCoordinate artifactCoordinate = new DefaultArtifactCoordinate();
+        artifactCoordinate.setGroupId( dependableCoordinate.getGroupId() );
+        artifactCoordinate.setArtifactId( dependableCoordinate.getArtifactId() );
+        artifactCoordinate.setVersion( dependableCoordinate.getVersion() );
+        artifactCoordinate.setClassifier( dependableCoordinate.getClassifier() );
+        artifactCoordinate.setExtension( artifactHandler.getExtension() );
+        return artifactCoordinate;
+    }
+
+    ArtifactRepository parseRepository( String repo, ArtifactRepositoryPolicy policy )
+            throws MojoFailureException
+    {
+        // if it's a simple url
+        String id = "temp";
+        ArtifactRepositoryLayout layout = getLayout( "default" );
+        String url = repo;
+
+        // if it's an extended repo URL of the form id::layout::url
+        if ( repo.contains( "::" ) )
+        {
+            Matcher matcher = ALT_REPO_SYNTAX_PATTERN.matcher( repo );
+            if ( !matcher.matches() )
+            {
+                throw new MojoFailureException( repo, "Invalid syntax for repository: " + repo,
+                        "Invalid syntax for repository. Use \"id::layout::url\" or \"URL\"." );
+            }
+
+            id = matcher.group( 1 ).trim();
+            if ( !StringUtils.isEmpty( matcher.group( 2 ) ) )
+            {
+                layout = getLayout( matcher.group( 2 ).trim() );
+            }
+            url = matcher.group( 3 ).trim();
+        }
+        return new MavenArtifactRepository( id, url, layout, policy, policy );
+    }
+
+    private ArtifactRepositoryLayout getLayout( String id )
+            throws MojoFailureException
+    {
+        ArtifactRepositoryLayout layout = repositoryLayouts.get( id );
+
+        if ( layout == null )
+        {
+            throw new MojoFailureException( id, "Invalid repository layout", "Invalid repository layout: " + id );
+        }
+
+        return layout;
+    }
+
+    /**
+     * @return {@link #skip}
+     */
+    protected boolean isSkip()
+    {
+        return skip;
+    }
+
+    protected boolean isTransitive()
+    {
+        return transitive;
+    }
+
+    protected DefaultDependableCoordinate getCoordinate()
+    {
+        return coordinate;
+    }
+
+    protected DependencyResolver getDependencyResolver()
+    {
+        return dependencyResolver;
+    }
+
+    protected ArtifactResolver getArtifactResolver()
+    {
+        return artifactResolver;
+    }
+
+    /**
+     * @param artifact The artifact
+     */
+    public void setArtifact( String artifact )
+    {
+        this.artifact = artifact;
+    }
+
+    /**
+     * @param groupId The groupId.
+     */
+    public void setGroupId( String groupId )
+    {
+        this.coordinate.setGroupId( groupId );
+    }
+
+    /**
+     * @param artifactId The artifactId.

Review comment:
       artifact ID

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();
+
+        while ( e.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) e.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( name.length() <= 6 || !name.substring( name.length() - 6 ).equals( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );
+        }
+        jarFile.close();
+    }
+
+    public ProjectBuildingRequest buildBuildingRequest()
+            throws MojoExecutionException, MojoFailureException
+    {
+        if ( artifact == null )
+        {
+            throw new MojoFailureException( "You must specify an artifact, "
+                    + "e.g. -Dartifact=org.apache.maven.plugins:maven-downloader-plugin:1.0" );
+        }
+        if ( artifact != null )
+        {
+            String[] tokens = StringUtils.split( artifact, ":" );
+            if ( tokens.length < 3 || tokens.length > 5 )
+            {
+                throw new MojoFailureException( "Invalid artifact, you must specify "
+                        + "groupId:artifactId:version[:packaging[:classifier]] " + artifact );
+            }
+            coordinate.setGroupId( tokens[0] );
+            coordinate.setArtifactId( tokens[1] );
+            coordinate.setVersion( tokens[2] );
+            if ( tokens.length >= 4 )
+            {
+                coordinate.setType( tokens[3] );
+            }
+            if ( tokens.length == 5 )
+            {
+                coordinate.setClassifier( tokens[4] );
+            }
+        }
+
+        ArtifactRepositoryPolicy always =
+                new ArtifactRepositoryPolicy( true, ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
+                        ArtifactRepositoryPolicy.CHECKSUM_POLICY_WARN );
+
+        List<ArtifactRepository> repoList = new ArrayList<>();
+
+        if ( pomRemoteRepositories != null )
+        {
+            repoList.addAll( pomRemoteRepositories );
+        }
+
+        if ( remoteRepositories != null )
+        {
+            // Use the same format as in the deploy plugin id::layout::url
+            String[] repos = StringUtils.split( remoteRepositories, "," );
+            for ( String repo : repos )
+            {
+                repoList.add( parseRepository( repo, always ) );
+            }
+        }
+
+        ProjectBuildingRequest buildingRequest =
+                new DefaultProjectBuildingRequest( session.getProjectBuildingRequest() );
+
+        Settings settings = session.getSettings();
+        repositorySystem.injectMirror( repoList, settings.getMirrors() );
+        repositorySystem.injectProxy( repoList, settings.getProxies() );
+        repositorySystem.injectAuthentication( repoList, settings.getServers() );
+
+        buildingRequest.setRemoteRepositories( repoList );
+
+        return buildingRequest;
+    }
+
+    protected ArtifactCoordinate toArtifactCoordinate( DependableCoordinate dependableCoordinate )
+    {
+        ArtifactHandler artifactHandler = artifactHandlerManager.getArtifactHandler( dependableCoordinate.getType() );
+        DefaultArtifactCoordinate artifactCoordinate = new DefaultArtifactCoordinate();
+        artifactCoordinate.setGroupId( dependableCoordinate.getGroupId() );
+        artifactCoordinate.setArtifactId( dependableCoordinate.getArtifactId() );
+        artifactCoordinate.setVersion( dependableCoordinate.getVersion() );
+        artifactCoordinate.setClassifier( dependableCoordinate.getClassifier() );
+        artifactCoordinate.setExtension( artifactHandler.getExtension() );
+        return artifactCoordinate;
+    }
+
+    ArtifactRepository parseRepository( String repo, ArtifactRepositoryPolicy policy )
+            throws MojoFailureException
+    {
+        // if it's a simple url
+        String id = "temp";
+        ArtifactRepositoryLayout layout = getLayout( "default" );
+        String url = repo;
+
+        // if it's an extended repo URL of the form id::layout::url
+        if ( repo.contains( "::" ) )
+        {
+            Matcher matcher = ALT_REPO_SYNTAX_PATTERN.matcher( repo );
+            if ( !matcher.matches() )
+            {
+                throw new MojoFailureException( repo, "Invalid syntax for repository: " + repo,
+                        "Invalid syntax for repository. Use \"id::layout::url\" or \"URL\"." );
+            }
+
+            id = matcher.group( 1 ).trim();
+            if ( !StringUtils.isEmpty( matcher.group( 2 ) ) )
+            {
+                layout = getLayout( matcher.group( 2 ).trim() );
+            }
+            url = matcher.group( 3 ).trim();
+        }
+        return new MavenArtifactRepository( id, url, layout, policy, policy );
+    }
+
+    private ArtifactRepositoryLayout getLayout( String id )
+            throws MojoFailureException
+    {
+        ArtifactRepositoryLayout layout = repositoryLayouts.get( id );
+
+        if ( layout == null )
+        {
+            throw new MojoFailureException( id, "Invalid repository layout", "Invalid repository layout: " + id );
+        }
+
+        return layout;
+    }
+
+    /**
+     * @return {@link #skip}
+     */
+    protected boolean isSkip()
+    {
+        return skip;
+    }
+
+    protected boolean isTransitive()
+    {
+        return transitive;
+    }
+
+    protected DefaultDependableCoordinate getCoordinate()
+    {
+        return coordinate;
+    }
+
+    protected DependencyResolver getDependencyResolver()
+    {
+        return dependencyResolver;
+    }
+
+    protected ArtifactResolver getArtifactResolver()
+    {
+        return artifactResolver;
+    }
+
+    /**
+     * @param artifact The artifact

Review comment:
       doc comments begin with lower case, per Oracle guidelines

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,396 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver().resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver().resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();
+
+        while ( e.hasMoreElements() )
+        {
+            JarEntry entry = ( JarEntry )e.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( name.length() <= 6 || !name.substring( name.length() - 6 ).equals( ".class" )) {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );

Review comment:
       I think logging is how we usually do this. The log can be injected or tested.

##########
File path: src/test/java/org/apache/maven/plugins/dependency/TestGetClassesMojo.java
##########
@@ -0,0 +1,86 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.LegacySupport;
+import org.apache.maven.plugin.testing.stubs.MavenProjectStub;
+import org.apache.maven.settings.Server;
+import org.apache.maven.settings.Settings;
+import org.sonatype.aether.impl.internal.SimpleLocalRepositoryManager;

Review comment:
       Tricky but can we replace this with org.eclipse equivalents? Probably not a 1:1 replacement. 

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();

Review comment:
       e --> entries 
   
   In general, avoid single letter variable names except for loop counters

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.

Review comment:
       I don't think this should follow transitive dependencies

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.

Review comment:
       url, --> URLs,

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;

Review comment:
       please don't use this class any more. apache commons stringutils if you must. 

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.

Review comment:
       artifact ID

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();
+
+        while ( e.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) e.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( name.length() <= 6 || !name.substring( name.length() - 6 ).equals( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );
+        }
+        jarFile.close();
+    }
+
+    public ProjectBuildingRequest buildBuildingRequest()

Review comment:
       why is this public? Methods should have the most restrictive access possible.

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();
+
+        while ( e.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) e.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( name.length() <= 6 || !name.substring( name.length() - 6 ).equals( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );
+        }
+        jarFile.close();
+    }
+
+    public ProjectBuildingRequest buildBuildingRequest()
+            throws MojoExecutionException, MojoFailureException
+    {
+        if ( artifact == null )
+        {
+            throw new MojoFailureException( "You must specify an artifact, "
+                    + "e.g. -Dartifact=org.apache.maven.plugins:maven-downloader-plugin:1.0" );
+        }
+        if ( artifact != null )
+        {
+            String[] tokens = StringUtils.split( artifact, ":" );
+            if ( tokens.length < 3 || tokens.length > 5 )
+            {
+                throw new MojoFailureException( "Invalid artifact, you must specify "
+                        + "groupId:artifactId:version[:packaging[:classifier]] " + artifact );
+            }
+            coordinate.setGroupId( tokens[0] );
+            coordinate.setArtifactId( tokens[1] );
+            coordinate.setVersion( tokens[2] );
+            if ( tokens.length >= 4 )
+            {
+                coordinate.setType( tokens[3] );
+            }
+            if ( tokens.length == 5 )
+            {
+                coordinate.setClassifier( tokens[4] );
+            }
+        }
+
+        ArtifactRepositoryPolicy always =
+                new ArtifactRepositoryPolicy( true, ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
+                        ArtifactRepositoryPolicy.CHECKSUM_POLICY_WARN );
+
+        List<ArtifactRepository> repoList = new ArrayList<>();
+
+        if ( pomRemoteRepositories != null )
+        {
+            repoList.addAll( pomRemoteRepositories );
+        }
+
+        if ( remoteRepositories != null )
+        {
+            // Use the same format as in the deploy plugin id::layout::url
+            String[] repos = StringUtils.split( remoteRepositories, "," );
+            for ( String repo : repos )
+            {
+                repoList.add( parseRepository( repo, always ) );
+            }
+        }
+
+        ProjectBuildingRequest buildingRequest =
+                new DefaultProjectBuildingRequest( session.getProjectBuildingRequest() );
+
+        Settings settings = session.getSettings();
+        repositorySystem.injectMirror( repoList, settings.getMirrors() );
+        repositorySystem.injectProxy( repoList, settings.getProxies() );
+        repositorySystem.injectAuthentication( repoList, settings.getServers() );
+
+        buildingRequest.setRemoteRepositories( repoList );
+
+        return buildingRequest;
+    }
+
+    protected ArtifactCoordinate toArtifactCoordinate( DependableCoordinate dependableCoordinate )
+    {
+        ArtifactHandler artifactHandler = artifactHandlerManager.getArtifactHandler( dependableCoordinate.getType() );
+        DefaultArtifactCoordinate artifactCoordinate = new DefaultArtifactCoordinate();
+        artifactCoordinate.setGroupId( dependableCoordinate.getGroupId() );
+        artifactCoordinate.setArtifactId( dependableCoordinate.getArtifactId() );
+        artifactCoordinate.setVersion( dependableCoordinate.getVersion() );
+        artifactCoordinate.setClassifier( dependableCoordinate.getClassifier() );
+        artifactCoordinate.setExtension( artifactHandler.getExtension() );
+        return artifactCoordinate;
+    }
+
+    ArtifactRepository parseRepository( String repo, ArtifactRepositoryPolicy policy )
+            throws MojoFailureException
+    {
+        // if it's a simple url
+        String id = "temp";
+        ArtifactRepositoryLayout layout = getLayout( "default" );
+        String url = repo;

Review comment:
       why copy this value?

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()

Review comment:
       you can access fields like dependencyResolver directly. There's no need to use a getter method in the same class. 

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. ie.

Review comment:
       avoid Latin. ie. --> That is,

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );

Review comment:
       exception message should contain coordinates of artifact it was trying to download

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    private void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration entries = jarFile.entries();
+
+        while ( entries.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) entries.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( !name.endsWith( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );
+        }
+        jarFile.close();
+    }
+
+    private ProjectBuildingRequest buildBuildingRequest()

Review comment:
       makeBuildingRequest?

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    private void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration entries = jarFile.entries();
+
+        while ( entries.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) entries.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( !name.endsWith( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );

Review comment:
       try to avoid reusing local variables. Here you have two things: an entry name and a class name, so two different variables make this clearer

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    private void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration entries = jarFile.entries();
+
+        while ( entries.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) entries.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( !name.endsWith( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );
+        }
+        jarFile.close();
+    }
+
+    private ProjectBuildingRequest buildBuildingRequest()
+            throws MojoExecutionException, MojoFailureException
+    {
+        if ( artifact == null )
+        {
+            throw new MojoFailureException( "You must specify an artifact, "
+                    + "e.g. -Dartifact=org.apache.maven.plugins:maven-downloader-plugin:1.0" );
+        }
+        if ( artifact != null )
+        {
+            String[] tokens = artifact.split( ":" );
+            if ( tokens.length < 3 || tokens.length > 5 )
+            {
+                throw new MojoFailureException( "Invalid artifact, you must specify "
+                        + "groupId:artifactId:version[:packaging[:classifier]] " + artifact );
+            }
+            coordinate.setGroupId( tokens[0] );
+            coordinate.setArtifactId( tokens[1] );
+            coordinate.setVersion( tokens[2] );
+            if ( tokens.length >= 4 )
+            {
+                coordinate.setType( tokens[3] );
+            }
+            if ( tokens.length == 5 )
+            {
+                coordinate.setClassifier( tokens[4] );
+            }
+        }
+
+        ArtifactRepositoryPolicy always =
+                new ArtifactRepositoryPolicy( true, ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
+                        ArtifactRepositoryPolicy.CHECKSUM_POLICY_WARN );
+
+        List<ArtifactRepository> repoList = new ArrayList<>();
+
+        if ( pomRemoteRepositories != null )
+        {
+            repoList.addAll( pomRemoteRepositories );
+        }
+
+        if ( remoteRepositories != null )
+        {
+            // Use the same format as in the deploy plugin id::layout::url
+            String[] repos = remoteRepositories.split( "," );
+            for ( String repo : repos )
+            {
+                repoList.add( parseRepository( repo, always ) );
+            }
+        }
+
+        ProjectBuildingRequest buildingRequest =
+                new DefaultProjectBuildingRequest( session.getProjectBuildingRequest() );
+
+        Settings settings = session.getSettings();
+        repositorySystem.injectMirror( repoList, settings.getMirrors() );
+        repositorySystem.injectProxy( repoList, settings.getProxies() );
+        repositorySystem.injectAuthentication( repoList, settings.getServers() );
+
+        buildingRequest.setRemoteRepositories( repoList );
+
+        return buildingRequest;
+    }
+
+    protected ArtifactCoordinate toArtifactCoordinate( DependableCoordinate dependableCoordinate )
+    {
+        ArtifactHandler artifactHandler = artifactHandlerManager.getArtifactHandler( dependableCoordinate.getType() );
+        DefaultArtifactCoordinate artifactCoordinate = new DefaultArtifactCoordinate();
+        artifactCoordinate.setGroupId( dependableCoordinate.getGroupId() );
+        artifactCoordinate.setArtifactId( dependableCoordinate.getArtifactId() );
+        artifactCoordinate.setVersion( dependableCoordinate.getVersion() );
+        artifactCoordinate.setClassifier( dependableCoordinate.getClassifier() );
+        artifactCoordinate.setExtension( artifactHandler.getExtension() );
+        return artifactCoordinate;
+    }
+
+    ArtifactRepository parseRepository( String repo, ArtifactRepositoryPolicy policy )
+            throws MojoFailureException
+    {
+        // if it's a simple url
+        String id = "temp";
+        ArtifactRepositoryLayout layout = getLayout( "default" );
+
+        // if it's an extended repo URL of the form id::layout::url
+        if ( repo.contains( "::" ) )
+        {
+            Matcher matcher = ALT_REPO_SYNTAX_PATTERN.matcher( repo );
+            if ( !matcher.matches() )
+            {
+                throw new MojoFailureException( repo, "Invalid syntax for repository: " + repo,
+                        "Invalid syntax for repository. Use \"id::layout::url\" or \"URL\"." );
+            }
+
+            id = matcher.group( 1 ).trim();
+            if ( !( matcher.group( 2 ) == null || matcher.group( 2 ).trim().isEmpty() ) )
+            {
+                layout = getLayout( matcher.group( 2 ).trim() );
+            }
+            repo = matcher.group( 3 ).trim();
+        }
+        return new MavenArtifactRepository( id, repo, layout, policy, policy );
+    }
+
+    private ArtifactRepositoryLayout getLayout( String id )
+            throws MojoFailureException
+    {
+        ArtifactRepositoryLayout layout = repositoryLayouts.get( id );
+
+        if ( layout == null )
+        {
+            throw new MojoFailureException( id, "Invalid repository layout", "Invalid repository layout: " + id );
+        }
+
+        return layout;
+    }
+
+    /**
+     * @return {@link #skip}
+     */
+    protected boolean isSkip()
+    {
+        return skip;
+    }
+
+    protected boolean isTransitive()
+    {
+        return transitive;
+    }
+
+    protected DefaultDependableCoordinate getCoordinate()
+    {
+        return coordinate;
+    }
+
+    protected DependencyResolver getDependencyResolver()
+    {
+        return dependencyResolver;
+    }
+
+    protected ArtifactResolver getArtifactResolver()

Review comment:
       do you need this method?

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();

Review comment:
       don't shadow the field here

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    private void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration entries = jarFile.entries();
+
+        while ( entries.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) entries.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( !name.endsWith( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );
+        }
+        jarFile.close();
+    }
+
+    private ProjectBuildingRequest buildBuildingRequest()
+            throws MojoExecutionException, MojoFailureException
+    {
+        if ( artifact == null )
+        {
+            throw new MojoFailureException( "You must specify an artifact, "
+                    + "e.g. -Dartifact=org.apache.maven.plugins:maven-downloader-plugin:1.0" );
+        }
+        if ( artifact != null )
+        {
+            String[] tokens = artifact.split( ":" );
+            if ( tokens.length < 3 || tokens.length > 5 )
+            {
+                throw new MojoFailureException( "Invalid artifact, you must specify "
+                        + "groupId:artifactId:version[:packaging[:classifier]] " + artifact );
+            }
+            coordinate.setGroupId( tokens[0] );
+            coordinate.setArtifactId( tokens[1] );
+            coordinate.setVersion( tokens[2] );
+            if ( tokens.length >= 4 )
+            {
+                coordinate.setType( tokens[3] );
+            }
+            if ( tokens.length == 5 )
+            {
+                coordinate.setClassifier( tokens[4] );
+            }
+        }
+
+        ArtifactRepositoryPolicy always =
+                new ArtifactRepositoryPolicy( true, ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
+                        ArtifactRepositoryPolicy.CHECKSUM_POLICY_WARN );
+
+        List<ArtifactRepository> repoList = new ArrayList<>();
+
+        if ( pomRemoteRepositories != null )
+        {
+            repoList.addAll( pomRemoteRepositories );
+        }
+
+        if ( remoteRepositories != null )
+        {
+            // Use the same format as in the deploy plugin id::layout::url
+            String[] repos = remoteRepositories.split( "," );
+            for ( String repo : repos )
+            {
+                repoList.add( parseRepository( repo, always ) );
+            }
+        }
+
+        ProjectBuildingRequest buildingRequest =
+                new DefaultProjectBuildingRequest( session.getProjectBuildingRequest() );
+
+        Settings settings = session.getSettings();
+        repositorySystem.injectMirror( repoList, settings.getMirrors() );
+        repositorySystem.injectProxy( repoList, settings.getProxies() );
+        repositorySystem.injectAuthentication( repoList, settings.getServers() );
+
+        buildingRequest.setRemoteRepositories( repoList );
+
+        return buildingRequest;
+    }
+
+    protected ArtifactCoordinate toArtifactCoordinate( DependableCoordinate dependableCoordinate )
+    {
+        ArtifactHandler artifactHandler = artifactHandlerManager.getArtifactHandler( dependableCoordinate.getType() );
+        DefaultArtifactCoordinate artifactCoordinate = new DefaultArtifactCoordinate();
+        artifactCoordinate.setGroupId( dependableCoordinate.getGroupId() );
+        artifactCoordinate.setArtifactId( dependableCoordinate.getArtifactId() );
+        artifactCoordinate.setVersion( dependableCoordinate.getVersion() );
+        artifactCoordinate.setClassifier( dependableCoordinate.getClassifier() );
+        artifactCoordinate.setExtension( artifactHandler.getExtension() );
+        return artifactCoordinate;
+    }
+
+    ArtifactRepository parseRepository( String repo, ArtifactRepositoryPolicy policy )
+            throws MojoFailureException
+    {
+        // if it's a simple url
+        String id = "temp";
+        ArtifactRepositoryLayout layout = getLayout( "default" );
+
+        // if it's an extended repo URL of the form id::layout::url
+        if ( repo.contains( "::" ) )
+        {
+            Matcher matcher = ALT_REPO_SYNTAX_PATTERN.matcher( repo );
+            if ( !matcher.matches() )
+            {
+                throw new MojoFailureException( repo, "Invalid syntax for repository: " + repo,
+                        "Invalid syntax for repository. Use \"id::layout::url\" or \"URL\"." );
+            }
+
+            id = matcher.group( 1 ).trim();
+            if ( !( matcher.group( 2 ) == null || matcher.group( 2 ).trim().isEmpty() ) )
+            {
+                layout = getLayout( matcher.group( 2 ).trim() );
+            }
+            repo = matcher.group( 3 ).trim();
+        }
+        return new MavenArtifactRepository( id, repo, layout, policy, policy );
+    }
+
+    private ArtifactRepositoryLayout getLayout( String id )
+            throws MojoFailureException
+    {
+        ArtifactRepositoryLayout layout = repositoryLayouts.get( id );
+
+        if ( layout == null )
+        {
+            throw new MojoFailureException( id, "Invalid repository layout", "Invalid repository layout: " + id );
+        }
+
+        return layout;
+    }
+
+    /**
+     * @return {@link #skip}
+     */
+    protected boolean isSkip()
+    {
+        return skip;
+    }
+
+    protected boolean isTransitive()
+    {
+        return transitive;
+    }
+
+    protected DefaultDependableCoordinate getCoordinate()
+    {
+        return coordinate;
+    }
+
+    protected DependencyResolver getDependencyResolver()
+    {
+        return dependencyResolver;
+    }
+
+    protected ArtifactResolver getArtifactResolver()
+    {
+        return artifactResolver;
+    }
+
+    /**
+     * @param artifact The artifact.

Review comment:
       https://www.oracle.com/technical-resources/articles/java/javadoc-tool.html#tag

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();

Review comment:
       I don't understand the difference between this and an ArtifactCoordinate.




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[GitHub] [maven-dependency-plugin] jonvolfson commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r441029925



##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();

Review comment:
       fixed, forgot to comment




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[GitHub] [maven-dependency-plugin] jonvolfson commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r431278352



##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    private void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration entries = jarFile.entries();
+
+        while ( entries.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) entries.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( !name.endsWith( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );
+        }
+        jarFile.close();
+    }
+
+    private ProjectBuildingRequest buildBuildingRequest()
+            throws MojoExecutionException, MojoFailureException
+    {
+        if ( artifact == null )
+        {
+            throw new MojoFailureException( "You must specify an artifact, "
+                    + "e.g. -Dartifact=org.apache.maven.plugins:maven-downloader-plugin:1.0" );
+        }
+        if ( artifact != null )
+        {
+            String[] tokens = artifact.split( ":" );
+            if ( tokens.length < 3 || tokens.length > 5 )
+            {
+                throw new MojoFailureException( "Invalid artifact, you must specify "
+                        + "groupId:artifactId:version[:packaging[:classifier]] " + artifact );
+            }
+            coordinate.setGroupId( tokens[0] );
+            coordinate.setArtifactId( tokens[1] );
+            coordinate.setVersion( tokens[2] );
+            if ( tokens.length >= 4 )
+            {
+                coordinate.setType( tokens[3] );
+            }
+            if ( tokens.length == 5 )
+            {
+                coordinate.setClassifier( tokens[4] );
+            }
+        }
+
+        ArtifactRepositoryPolicy always =
+                new ArtifactRepositoryPolicy( true, ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
+                        ArtifactRepositoryPolicy.CHECKSUM_POLICY_WARN );
+
+        List<ArtifactRepository> repoList = new ArrayList<>();
+
+        if ( pomRemoteRepositories != null )
+        {
+            repoList.addAll( pomRemoteRepositories );
+        }
+
+        if ( remoteRepositories != null )
+        {
+            // Use the same format as in the deploy plugin id::layout::url
+            String[] repos = remoteRepositories.split( "," );
+            for ( String repo : repos )
+            {
+                repoList.add( parseRepository( repo, always ) );
+            }
+        }
+
+        ProjectBuildingRequest buildingRequest =
+                new DefaultProjectBuildingRequest( session.getProjectBuildingRequest() );
+
+        Settings settings = session.getSettings();
+        repositorySystem.injectMirror( repoList, settings.getMirrors() );
+        repositorySystem.injectProxy( repoList, settings.getProxies() );
+        repositorySystem.injectAuthentication( repoList, settings.getServers() );
+
+        buildingRequest.setRemoteRepositories( repoList );
+
+        return buildingRequest;
+    }
+
+    protected ArtifactCoordinate toArtifactCoordinate( DependableCoordinate dependableCoordinate )
+    {
+        ArtifactHandler artifactHandler = artifactHandlerManager.getArtifactHandler( dependableCoordinate.getType() );
+        DefaultArtifactCoordinate artifactCoordinate = new DefaultArtifactCoordinate();
+        artifactCoordinate.setGroupId( dependableCoordinate.getGroupId() );
+        artifactCoordinate.setArtifactId( dependableCoordinate.getArtifactId() );
+        artifactCoordinate.setVersion( dependableCoordinate.getVersion() );
+        artifactCoordinate.setClassifier( dependableCoordinate.getClassifier() );
+        artifactCoordinate.setExtension( artifactHandler.getExtension() );
+        return artifactCoordinate;
+    }
+
+    ArtifactRepository parseRepository( String repo, ArtifactRepositoryPolicy policy )
+            throws MojoFailureException
+    {
+        // if it's a simple url
+        String id = "temp";
+        ArtifactRepositoryLayout layout = getLayout( "default" );
+
+        // if it's an extended repo URL of the form id::layout::url
+        if ( repo.contains( "::" ) )
+        {
+            Matcher matcher = ALT_REPO_SYNTAX_PATTERN.matcher( repo );
+            if ( !matcher.matches() )
+            {
+                throw new MojoFailureException( repo, "Invalid syntax for repository: " + repo,
+                        "Invalid syntax for repository. Use \"id::layout::url\" or \"URL\"." );
+            }
+
+            id = matcher.group( 1 ).trim();
+            if ( !( matcher.group( 2 ) == null || matcher.group( 2 ).trim().isEmpty() ) )
+            {
+                layout = getLayout( matcher.group( 2 ).trim() );
+            }
+            repo = matcher.group( 3 ).trim();
+        }
+        return new MavenArtifactRepository( id, repo, layout, policy, policy );
+    }
+
+    private ArtifactRepositoryLayout getLayout( String id )
+            throws MojoFailureException
+    {
+        ArtifactRepositoryLayout layout = repositoryLayouts.get( id );
+
+        if ( layout == null )
+        {
+            throw new MojoFailureException( id, "Invalid repository layout", "Invalid repository layout: " + id );
+        }
+
+        return layout;
+    }
+
+    /**
+     * @return {@link #skip}
+     */
+    protected boolean isSkip()
+    {
+        return skip;
+    }
+
+    protected boolean isTransitive()
+    {
+        return transitive;
+    }
+
+    protected DefaultDependableCoordinate getCoordinate()
+    {
+        return coordinate;
+    }
+
+    protected DependencyResolver getDependencyResolver()
+    {
+        return dependencyResolver;
+    }
+
+    protected ArtifactResolver getArtifactResolver()

Review comment:
       fixed, removed this method and other getters that weren't needed

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. ie.

Review comment:
       fixed




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[GitHub] [maven-dependency-plugin] jonvolfson commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r430519833



##########
File path: src/test/java/org/apache/maven/plugins/dependency/TestGetClassesMojo.java
##########
@@ -0,0 +1,88 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.LegacySupport;
+import org.apache.maven.plugin.testing.stubs.MavenProjectStub;
+import org.apache.maven.settings.Server;
+import org.apache.maven.settings.Settings;
+import org.sonatype.aether.impl.internal.SimpleLocalRepositoryManager;
+import org.sonatype.aether.util.DefaultRepositorySystemSession;
+
+import java.io.File;
+
+public class TestGetClassesMojo
+        extends AbstractDependencyMojoTestCase
+{
+    GetClassesMojo mojo;
+
+    protected void setUp()
+            throws Exception
+    {
+        // required for mojo lookups to work
+        super.setUp( "markers", false );
+
+        File testPom = new File( getBasedir(), "target/test-classes/unit/get-test/plugin-config.xml" );
+        assert testPom.exists();
+        mojo = (GetClassesMojo) lookupMojo( "get-classes", testPom );
+
+        assertNotNull( mojo );
+
+        LegacySupport legacySupport = lookup( LegacySupport.class );
+        MavenSession session = newMavenSession( new MavenProjectStub() );
+        Settings settings = session.getSettings();
+        Server server = new Server();
+        server.setId( "myserver" );
+        server.setUsername( "foo" );
+        server.setPassword( "bar" );
+        settings.addServer( server );
+        legacySupport.setSession( session );
+        DefaultRepositorySystemSession repoSession =
+                (DefaultRepositorySystemSession) legacySupport.getRepositorySession();
+        repoSession.setLocalRepositoryManager( new SimpleLocalRepositoryManager( testDir.getAbsolutePath() ) );
+
+        setVariableValueToObject( mojo, "session", legacySupport.getSession() );
+    }
+
+    public void testGetClassesNotTransitive()
+            throws Exception
+    {
+        setVariableValueToObject( mojo, "remoteRepositories", "central::default::https://repo.maven.apache.org/maven2,"
+                + "central::::https://repo.maven.apache.org/maven2," + "https://repo.maven.apache.org/maven2" );
+        mojo.setArtifact("org.apache.commons:commons-lang3:3.6");
+        setVariableValueToObject( mojo, "transitive", Boolean.FALSE );
+
+        mojo.execute();
+        return;
+    }
+
+    public void testGetClassesTransitive()

Review comment:
       When listing classes for something like org.apache.maven:maven-model:2.0.9, setting -Dtransitive=true lists more classes than the false alternative. It's possible that the artifact used in the test has little/no transitive dependencies which means the results would be similar/the same.

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,396 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver().resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver().resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();
+
+        while ( e.hasMoreElements() )
+        {
+            JarEntry entry = ( JarEntry )e.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( name.length() <= 6 || !name.substring( name.length() - 6 ).equals( ".class" )) {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );
+        }
+        jarFile.close();
+    }
+
+    public ProjectBuildingRequest buildBuildingRequest()
+            throws MojoExecutionException, MojoFailureException
+    {
+        if ( coordinate.getArtifactId() == null && artifact == null )

Review comment:
       Fixed. Removed the coordinate.getArtifactId() part. This was recycled code from the GetMojo with a similar use case.

##########
File path: src/test/java/org/apache/maven/plugins/dependency/TestGetClassesMojo.java
##########
@@ -0,0 +1,88 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.LegacySupport;
+import org.apache.maven.plugin.testing.stubs.MavenProjectStub;
+import org.apache.maven.settings.Server;
+import org.apache.maven.settings.Settings;
+import org.sonatype.aether.impl.internal.SimpleLocalRepositoryManager;
+import org.sonatype.aether.util.DefaultRepositorySystemSession;
+
+import java.io.File;
+
+public class TestGetClassesMojo
+        extends AbstractDependencyMojoTestCase
+{
+    GetClassesMojo mojo;
+
+    protected void setUp()
+            throws Exception
+    {
+        // required for mojo lookups to work
+        super.setUp( "markers", false );
+
+        File testPom = new File( getBasedir(), "target/test-classes/unit/get-test/plugin-config.xml" );
+        assert testPom.exists();
+        mojo = (GetClassesMojo) lookupMojo( "get-classes", testPom );
+
+        assertNotNull( mojo );
+
+        LegacySupport legacySupport = lookup( LegacySupport.class );
+        MavenSession session = newMavenSession( new MavenProjectStub() );
+        Settings settings = session.getSettings();
+        Server server = new Server();
+        server.setId( "myserver" );
+        server.setUsername( "foo" );
+        server.setPassword( "bar" );
+        settings.addServer( server );
+        legacySupport.setSession( session );
+        DefaultRepositorySystemSession repoSession =
+                (DefaultRepositorySystemSession) legacySupport.getRepositorySession();
+        repoSession.setLocalRepositoryManager( new SimpleLocalRepositoryManager( testDir.getAbsolutePath() ) );
+
+        setVariableValueToObject( mojo, "session", legacySupport.getSession() );
+    }
+
+    public void testGetClassesNotTransitive()
+            throws Exception
+    {
+        setVariableValueToObject( mojo, "remoteRepositories", "central::default::https://repo.maven.apache.org/maven2,"
+                + "central::::https://repo.maven.apache.org/maven2," + "https://repo.maven.apache.org/maven2" );
+        mojo.setArtifact("org.apache.commons:commons-lang3:3.6");
+        setVariableValueToObject( mojo, "transitive", Boolean.FALSE );
+
+        mojo.execute();
+        return;

Review comment:
       Fixed.

##########
File path: src/test/java/org/apache/maven/plugins/dependency/TestGetClassesMojo.java
##########
@@ -0,0 +1,88 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.LegacySupport;
+import org.apache.maven.plugin.testing.stubs.MavenProjectStub;
+import org.apache.maven.settings.Server;
+import org.apache.maven.settings.Settings;
+import org.sonatype.aether.impl.internal.SimpleLocalRepositoryManager;
+import org.sonatype.aether.util.DefaultRepositorySystemSession;
+
+import java.io.File;
+
+public class TestGetClassesMojo
+        extends AbstractDependencyMojoTestCase
+{
+    GetClassesMojo mojo;
+
+    protected void setUp()
+            throws Exception
+    {
+        // required for mojo lookups to work
+        super.setUp( "markers", false );
+
+        File testPom = new File( getBasedir(), "target/test-classes/unit/get-test/plugin-config.xml" );
+        assert testPom.exists();
+        mojo = (GetClassesMojo) lookupMojo( "get-classes", testPom );
+
+        assertNotNull( mojo );
+
+        LegacySupport legacySupport = lookup( LegacySupport.class );
+        MavenSession session = newMavenSession( new MavenProjectStub() );
+        Settings settings = session.getSettings();
+        Server server = new Server();
+        server.setId( "myserver" );
+        server.setUsername( "foo" );
+        server.setPassword( "bar" );
+        settings.addServer( server );
+        legacySupport.setSession( session );
+        DefaultRepositorySystemSession repoSession =
+                (DefaultRepositorySystemSession) legacySupport.getRepositorySession();
+        repoSession.setLocalRepositoryManager( new SimpleLocalRepositoryManager( testDir.getAbsolutePath() ) );
+
+        setVariableValueToObject( mojo, "session", legacySupport.getSession() );
+    }
+
+    public void testGetClassesNotTransitive()
+            throws Exception
+    {
+        setVariableValueToObject( mojo, "remoteRepositories", "central::default::https://repo.maven.apache.org/maven2,"
+                + "central::::https://repo.maven.apache.org/maven2," + "https://repo.maven.apache.org/maven2" );
+        mojo.setArtifact("org.apache.commons:commons-lang3:3.6");
+        setVariableValueToObject( mojo, "transitive", Boolean.FALSE );
+
+        mojo.execute();
+        return;
+    }
+
+    public void testGetClassesTransitive()
+            throws Exception
+    {
+        setVariableValueToObject( mojo, "remoteRepositories", "central::default::https://repo.maven.apache.org/maven2,"
+                + "central::::https://repo.maven.apache.org/maven2," + "https://repo.maven.apache.org/maven2" );
+        mojo.setArtifact("org.apache.commons:commons-lang3:3.6");
+        setVariableValueToObject( mojo, "transitive", Boolean.TRUE );
+
+        mojo.execute();
+        return;

Review comment:
       Fixed.

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.

Review comment:
       I'm not sure if this is a useful feature to have but in case it is, I've set the default to false for now instead of removing it altogether.

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.

Review comment:
       fixed

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo

Review comment:
       fixed

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.

Review comment:
       fixed

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.

Review comment:
       fixed

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();
+
+        while ( e.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) e.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( name.length() <= 6 || !name.substring( name.length() - 6 ).equals( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );
+        }
+        jarFile.close();
+    }
+
+    public ProjectBuildingRequest buildBuildingRequest()
+            throws MojoExecutionException, MojoFailureException
+    {
+        if ( artifact == null )
+        {
+            throw new MojoFailureException( "You must specify an artifact, "
+                    + "e.g. -Dartifact=org.apache.maven.plugins:maven-downloader-plugin:1.0" );
+        }
+        if ( artifact != null )
+        {
+            String[] tokens = StringUtils.split( artifact, ":" );
+            if ( tokens.length < 3 || tokens.length > 5 )
+            {
+                throw new MojoFailureException( "Invalid artifact, you must specify "
+                        + "groupId:artifactId:version[:packaging[:classifier]] " + artifact );
+            }
+            coordinate.setGroupId( tokens[0] );
+            coordinate.setArtifactId( tokens[1] );
+            coordinate.setVersion( tokens[2] );
+            if ( tokens.length >= 4 )
+            {
+                coordinate.setType( tokens[3] );
+            }
+            if ( tokens.length == 5 )
+            {
+                coordinate.setClassifier( tokens[4] );
+            }
+        }
+
+        ArtifactRepositoryPolicy always =
+                new ArtifactRepositoryPolicy( true, ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
+                        ArtifactRepositoryPolicy.CHECKSUM_POLICY_WARN );
+
+        List<ArtifactRepository> repoList = new ArrayList<>();
+
+        if ( pomRemoteRepositories != null )
+        {
+            repoList.addAll( pomRemoteRepositories );
+        }
+
+        if ( remoteRepositories != null )
+        {
+            // Use the same format as in the deploy plugin id::layout::url
+            String[] repos = StringUtils.split( remoteRepositories, "," );
+            for ( String repo : repos )
+            {
+                repoList.add( parseRepository( repo, always ) );
+            }
+        }
+
+        ProjectBuildingRequest buildingRequest =
+                new DefaultProjectBuildingRequest( session.getProjectBuildingRequest() );
+
+        Settings settings = session.getSettings();
+        repositorySystem.injectMirror( repoList, settings.getMirrors() );
+        repositorySystem.injectProxy( repoList, settings.getProxies() );
+        repositorySystem.injectAuthentication( repoList, settings.getServers() );
+
+        buildingRequest.setRemoteRepositories( repoList );
+
+        return buildingRequest;
+    }
+
+    protected ArtifactCoordinate toArtifactCoordinate( DependableCoordinate dependableCoordinate )
+    {
+        ArtifactHandler artifactHandler = artifactHandlerManager.getArtifactHandler( dependableCoordinate.getType() );
+        DefaultArtifactCoordinate artifactCoordinate = new DefaultArtifactCoordinate();
+        artifactCoordinate.setGroupId( dependableCoordinate.getGroupId() );
+        artifactCoordinate.setArtifactId( dependableCoordinate.getArtifactId() );
+        artifactCoordinate.setVersion( dependableCoordinate.getVersion() );
+        artifactCoordinate.setClassifier( dependableCoordinate.getClassifier() );
+        artifactCoordinate.setExtension( artifactHandler.getExtension() );
+        return artifactCoordinate;
+    }
+
+    ArtifactRepository parseRepository( String repo, ArtifactRepositoryPolicy policy )
+            throws MojoFailureException
+    {
+        // if it's a simple url
+        String id = "temp";
+        ArtifactRepositoryLayout layout = getLayout( "default" );
+        String url = repo;
+
+        // if it's an extended repo URL of the form id::layout::url
+        if ( repo.contains( "::" ) )
+        {
+            Matcher matcher = ALT_REPO_SYNTAX_PATTERN.matcher( repo );
+            if ( !matcher.matches() )
+            {
+                throw new MojoFailureException( repo, "Invalid syntax for repository: " + repo,
+                        "Invalid syntax for repository. Use \"id::layout::url\" or \"URL\"." );
+            }
+
+            id = matcher.group( 1 ).trim();
+            if ( !StringUtils.isEmpty( matcher.group( 2 ) ) )
+            {
+                layout = getLayout( matcher.group( 2 ).trim() );
+            }
+            url = matcher.group( 3 ).trim();
+        }
+        return new MavenArtifactRepository( id, url, layout, policy, policy );
+    }
+
+    private ArtifactRepositoryLayout getLayout( String id )
+            throws MojoFailureException
+    {
+        ArtifactRepositoryLayout layout = repositoryLayouts.get( id );
+
+        if ( layout == null )
+        {
+            throw new MojoFailureException( id, "Invalid repository layout", "Invalid repository layout: " + id );
+        }
+
+        return layout;
+    }
+
+    /**
+     * @return {@link #skip}
+     */
+    protected boolean isSkip()
+    {
+        return skip;
+    }
+
+    protected boolean isTransitive()
+    {
+        return transitive;
+    }
+
+    protected DefaultDependableCoordinate getCoordinate()
+    {
+        return coordinate;
+    }
+
+    protected DependencyResolver getDependencyResolver()
+    {
+        return dependencyResolver;
+    }
+
+    protected ArtifactResolver getArtifactResolver()
+    {
+        return artifactResolver;
+    }
+
+    /**
+     * @param artifact The artifact

Review comment:
       More clarification? This is taken from the GetMojo. 

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();
+
+        while ( e.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) e.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( name.length() <= 6 || !name.substring( name.length() - 6 ).equals( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );
+        }
+        jarFile.close();
+    }
+
+    public ProjectBuildingRequest buildBuildingRequest()
+            throws MojoExecutionException, MojoFailureException
+    {
+        if ( artifact == null )
+        {
+            throw new MojoFailureException( "You must specify an artifact, "
+                    + "e.g. -Dartifact=org.apache.maven.plugins:maven-downloader-plugin:1.0" );
+        }
+        if ( artifact != null )
+        {
+            String[] tokens = StringUtils.split( artifact, ":" );
+            if ( tokens.length < 3 || tokens.length > 5 )
+            {
+                throw new MojoFailureException( "Invalid artifact, you must specify "
+                        + "groupId:artifactId:version[:packaging[:classifier]] " + artifact );
+            }
+            coordinate.setGroupId( tokens[0] );
+            coordinate.setArtifactId( tokens[1] );
+            coordinate.setVersion( tokens[2] );
+            if ( tokens.length >= 4 )
+            {
+                coordinate.setType( tokens[3] );
+            }
+            if ( tokens.length == 5 )
+            {
+                coordinate.setClassifier( tokens[4] );
+            }
+        }
+
+        ArtifactRepositoryPolicy always =
+                new ArtifactRepositoryPolicy( true, ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
+                        ArtifactRepositoryPolicy.CHECKSUM_POLICY_WARN );
+
+        List<ArtifactRepository> repoList = new ArrayList<>();
+
+        if ( pomRemoteRepositories != null )
+        {
+            repoList.addAll( pomRemoteRepositories );
+        }
+
+        if ( remoteRepositories != null )
+        {
+            // Use the same format as in the deploy plugin id::layout::url
+            String[] repos = StringUtils.split( remoteRepositories, "," );
+            for ( String repo : repos )
+            {
+                repoList.add( parseRepository( repo, always ) );
+            }
+        }
+
+        ProjectBuildingRequest buildingRequest =
+                new DefaultProjectBuildingRequest( session.getProjectBuildingRequest() );
+
+        Settings settings = session.getSettings();
+        repositorySystem.injectMirror( repoList, settings.getMirrors() );
+        repositorySystem.injectProxy( repoList, settings.getProxies() );
+        repositorySystem.injectAuthentication( repoList, settings.getServers() );
+
+        buildingRequest.setRemoteRepositories( repoList );
+
+        return buildingRequest;
+    }
+
+    protected ArtifactCoordinate toArtifactCoordinate( DependableCoordinate dependableCoordinate )
+    {
+        ArtifactHandler artifactHandler = artifactHandlerManager.getArtifactHandler( dependableCoordinate.getType() );
+        DefaultArtifactCoordinate artifactCoordinate = new DefaultArtifactCoordinate();
+        artifactCoordinate.setGroupId( dependableCoordinate.getGroupId() );
+        artifactCoordinate.setArtifactId( dependableCoordinate.getArtifactId() );
+        artifactCoordinate.setVersion( dependableCoordinate.getVersion() );
+        artifactCoordinate.setClassifier( dependableCoordinate.getClassifier() );
+        artifactCoordinate.setExtension( artifactHandler.getExtension() );
+        return artifactCoordinate;
+    }
+
+    ArtifactRepository parseRepository( String repo, ArtifactRepositoryPolicy policy )
+            throws MojoFailureException
+    {
+        // if it's a simple url
+        String id = "temp";
+        ArtifactRepositoryLayout layout = getLayout( "default" );
+        String url = repo;
+
+        // if it's an extended repo URL of the form id::layout::url
+        if ( repo.contains( "::" ) )
+        {
+            Matcher matcher = ALT_REPO_SYNTAX_PATTERN.matcher( repo );
+            if ( !matcher.matches() )
+            {
+                throw new MojoFailureException( repo, "Invalid syntax for repository: " + repo,
+                        "Invalid syntax for repository. Use \"id::layout::url\" or \"URL\"." );
+            }
+
+            id = matcher.group( 1 ).trim();
+            if ( !StringUtils.isEmpty( matcher.group( 2 ) ) )
+            {
+                layout = getLayout( matcher.group( 2 ).trim() );
+            }
+            url = matcher.group( 3 ).trim();
+        }
+        return new MavenArtifactRepository( id, url, layout, policy, policy );
+    }
+
+    private ArtifactRepositoryLayout getLayout( String id )
+            throws MojoFailureException
+    {
+        ArtifactRepositoryLayout layout = repositoryLayouts.get( id );
+
+        if ( layout == null )
+        {
+            throw new MojoFailureException( id, "Invalid repository layout", "Invalid repository layout: " + id );
+        }
+
+        return layout;
+    }
+
+    /**
+     * @return {@link #skip}
+     */
+    protected boolean isSkip()
+    {
+        return skip;
+    }
+
+    protected boolean isTransitive()
+    {
+        return transitive;
+    }
+
+    protected DefaultDependableCoordinate getCoordinate()
+    {
+        return coordinate;
+    }
+
+    protected DependencyResolver getDependencyResolver()
+    {
+        return dependencyResolver;
+    }
+
+    protected ArtifactResolver getArtifactResolver()
+    {
+        return artifactResolver;
+    }
+
+    /**
+     * @param artifact The artifact
+     */
+    public void setArtifact( String artifact )
+    {
+        this.artifact = artifact;
+    }
+
+    /**
+     * @param groupId The groupId.
+     */
+    public void setGroupId( String groupId )
+    {
+        this.coordinate.setGroupId( groupId );
+    }
+
+    /**
+     * @param artifactId The artifactId.

Review comment:
       fixed

##########
File path: src/test/java/org/apache/maven/plugins/dependency/TestGetClassesMojo.java
##########
@@ -0,0 +1,86 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.LegacySupport;
+import org.apache.maven.plugin.testing.stubs.MavenProjectStub;
+import org.apache.maven.settings.Server;
+import org.apache.maven.settings.Settings;
+import org.sonatype.aether.impl.internal.SimpleLocalRepositoryManager;
+import org.sonatype.aether.util.DefaultRepositorySystemSession;
+
+import java.io.File;
+
+public class TestGetClassesMojo
+        extends AbstractDependencyMojoTestCase
+{
+    GetClassesMojo mojo;
+
+    protected void setUp()
+            throws Exception
+    {
+        // required for mojo lookups to work
+        super.setUp( "markers", false );
+
+        File testPom = new File( getBasedir(), "target/test-classes/unit/get-test/plugin-config.xml" );
+        assert testPom.exists();

Review comment:
       fixed




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[GitHub] [maven-dependency-plugin] jonvolfson commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r441031230



##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();
+
+        while ( e.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) e.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( name.length() <= 6 || !name.substring( name.length() - 6 ).equals( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );
+        }
+        jarFile.close();
+    }
+
+    public ProjectBuildingRequest buildBuildingRequest()
+            throws MojoExecutionException, MojoFailureException
+    {
+        if ( artifact == null )
+        {
+            throw new MojoFailureException( "You must specify an artifact, "
+                    + "e.g. -Dartifact=org.apache.maven.plugins:maven-downloader-plugin:1.0" );
+        }
+        if ( artifact != null )
+        {
+            String[] tokens = StringUtils.split( artifact, ":" );
+            if ( tokens.length < 3 || tokens.length > 5 )
+            {
+                throw new MojoFailureException( "Invalid artifact, you must specify "
+                        + "groupId:artifactId:version[:packaging[:classifier]] " + artifact );
+            }
+            coordinate.setGroupId( tokens[0] );
+            coordinate.setArtifactId( tokens[1] );
+            coordinate.setVersion( tokens[2] );
+            if ( tokens.length >= 4 )
+            {
+                coordinate.setType( tokens[3] );
+            }
+            if ( tokens.length == 5 )
+            {
+                coordinate.setClassifier( tokens[4] );
+            }
+        }
+
+        ArtifactRepositoryPolicy always =
+                new ArtifactRepositoryPolicy( true, ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
+                        ArtifactRepositoryPolicy.CHECKSUM_POLICY_WARN );
+
+        List<ArtifactRepository> repoList = new ArrayList<>();
+
+        if ( pomRemoteRepositories != null )
+        {
+            repoList.addAll( pomRemoteRepositories );
+        }
+
+        if ( remoteRepositories != null )
+        {
+            // Use the same format as in the deploy plugin id::layout::url
+            String[] repos = StringUtils.split( remoteRepositories, "," );
+            for ( String repo : repos )
+            {
+                repoList.add( parseRepository( repo, always ) );
+            }
+        }
+
+        ProjectBuildingRequest buildingRequest =
+                new DefaultProjectBuildingRequest( session.getProjectBuildingRequest() );
+
+        Settings settings = session.getSettings();
+        repositorySystem.injectMirror( repoList, settings.getMirrors() );
+        repositorySystem.injectProxy( repoList, settings.getProxies() );
+        repositorySystem.injectAuthentication( repoList, settings.getServers() );
+
+        buildingRequest.setRemoteRepositories( repoList );
+
+        return buildingRequest;
+    }
+
+    protected ArtifactCoordinate toArtifactCoordinate( DependableCoordinate dependableCoordinate )
+    {
+        ArtifactHandler artifactHandler = artifactHandlerManager.getArtifactHandler( dependableCoordinate.getType() );
+        DefaultArtifactCoordinate artifactCoordinate = new DefaultArtifactCoordinate();
+        artifactCoordinate.setGroupId( dependableCoordinate.getGroupId() );
+        artifactCoordinate.setArtifactId( dependableCoordinate.getArtifactId() );
+        artifactCoordinate.setVersion( dependableCoordinate.getVersion() );
+        artifactCoordinate.setClassifier( dependableCoordinate.getClassifier() );
+        artifactCoordinate.setExtension( artifactHandler.getExtension() );
+        return artifactCoordinate;
+    }
+
+    ArtifactRepository parseRepository( String repo, ArtifactRepositoryPolicy policy )
+            throws MojoFailureException
+    {
+        // if it's a simple url
+        String id = "temp";
+        ArtifactRepositoryLayout layout = getLayout( "default" );
+        String url = repo;

Review comment:
       fixed, removed unneeded variable




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[GitHub] [maven-dependency-plugin] khmarbaise commented on pull request #57: Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

khmarbaise commented on pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#issuecomment-634095974


   First please create an appropriate JIRA issue for that and describe the use case for this. 


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[GitHub] [maven-dependency-plugin] bimargulies-google commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

bimargulies-google commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r430506873



##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,396 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver().resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver().resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();
+
+        while ( e.hasMoreElements() )
+        {
+            JarEntry entry = ( JarEntry )e.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( name.length() <= 6 || !name.substring( name.length() - 6 ).equals( ".class" )) {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );
+        }
+        jarFile.close();
+    }
+
+    public ProjectBuildingRequest buildBuildingRequest()
+            throws MojoExecutionException, MojoFailureException
+    {
+        if ( coordinate.getArtifactId() == null && artifact == null )

Review comment:
       You don't use coordinate below. Are you missing an else clause? Is that the code that would run if someone used -DgroupId ... instead of -Dartifact?

##########
File path: src/test/java/org/apache/maven/plugins/dependency/TestGetClassesMojo.java
##########
@@ -0,0 +1,88 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.LegacySupport;
+import org.apache.maven.plugin.testing.stubs.MavenProjectStub;
+import org.apache.maven.settings.Server;
+import org.apache.maven.settings.Settings;
+import org.sonatype.aether.impl.internal.SimpleLocalRepositoryManager;
+import org.sonatype.aether.util.DefaultRepositorySystemSession;
+
+import java.io.File;
+
+public class TestGetClassesMojo
+        extends AbstractDependencyMojoTestCase
+{
+    GetClassesMojo mojo;
+
+    protected void setUp()
+            throws Exception
+    {
+        // required for mojo lookups to work
+        super.setUp( "markers", false );
+
+        File testPom = new File( getBasedir(), "target/test-classes/unit/get-test/plugin-config.xml" );
+        assert testPom.exists();
+        mojo = (GetClassesMojo) lookupMojo( "get-classes", testPom );
+
+        assertNotNull( mojo );
+
+        LegacySupport legacySupport = lookup( LegacySupport.class );
+        MavenSession session = newMavenSession( new MavenProjectStub() );
+        Settings settings = session.getSettings();
+        Server server = new Server();
+        server.setId( "myserver" );
+        server.setUsername( "foo" );
+        server.setPassword( "bar" );
+        settings.addServer( server );
+        legacySupport.setSession( session );
+        DefaultRepositorySystemSession repoSession =
+                (DefaultRepositorySystemSession) legacySupport.getRepositorySession();
+        repoSession.setLocalRepositoryManager( new SimpleLocalRepositoryManager( testDir.getAbsolutePath() ) );
+
+        setVariableValueToObject( mojo, "session", legacySupport.getSession() );
+    }
+
+    public void testGetClassesNotTransitive()
+            throws Exception
+    {
+        setVariableValueToObject( mojo, "remoteRepositories", "central::default::https://repo.maven.apache.org/maven2,"
+                + "central::::https://repo.maven.apache.org/maven2," + "https://repo.maven.apache.org/maven2" );
+        mojo.setArtifact("org.apache.commons:commons-lang3:3.6");
+        setVariableValueToObject( mojo, "transitive", Boolean.FALSE );
+
+        mojo.execute();
+        return;
+    }
+
+    public void testGetClassesTransitive()
+            throws Exception
+    {
+        setVariableValueToObject( mojo, "remoteRepositories", "central::default::https://repo.maven.apache.org/maven2,"
+                + "central::::https://repo.maven.apache.org/maven2," + "https://repo.maven.apache.org/maven2" );
+        mojo.setArtifact("org.apache.commons:commons-lang3:3.6");
+        setVariableValueToObject( mojo, "transitive", Boolean.TRUE );
+
+        mojo.execute();
+        return;

Review comment:
       No need for return.

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,396 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )

Review comment:
       I think you can remove all of the 'skip' processing; it's not terribly useful for a mojo intended for CLI.

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,396 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver().resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );

Review comment:
       Print the file name of the jar before printing its contents if you are printing more than one jar file's worth?

##########
File path: src/test/java/org/apache/maven/plugins/dependency/TestGetClassesMojo.java
##########
@@ -0,0 +1,88 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.LegacySupport;
+import org.apache.maven.plugin.testing.stubs.MavenProjectStub;
+import org.apache.maven.settings.Server;
+import org.apache.maven.settings.Settings;
+import org.sonatype.aether.impl.internal.SimpleLocalRepositoryManager;
+import org.sonatype.aether.util.DefaultRepositorySystemSession;
+
+import java.io.File;
+
+public class TestGetClassesMojo
+        extends AbstractDependencyMojoTestCase
+{
+    GetClassesMojo mojo;
+
+    protected void setUp()
+            throws Exception
+    {
+        // required for mojo lookups to work
+        super.setUp( "markers", false );
+
+        File testPom = new File( getBasedir(), "target/test-classes/unit/get-test/plugin-config.xml" );
+        assert testPom.exists();
+        mojo = (GetClassesMojo) lookupMojo( "get-classes", testPom );
+
+        assertNotNull( mojo );
+
+        LegacySupport legacySupport = lookup( LegacySupport.class );
+        MavenSession session = newMavenSession( new MavenProjectStub() );
+        Settings settings = session.getSettings();
+        Server server = new Server();
+        server.setId( "myserver" );
+        server.setUsername( "foo" );
+        server.setPassword( "bar" );
+        settings.addServer( server );
+        legacySupport.setSession( session );
+        DefaultRepositorySystemSession repoSession =
+                (DefaultRepositorySystemSession) legacySupport.getRepositorySession();
+        repoSession.setLocalRepositoryManager( new SimpleLocalRepositoryManager( testDir.getAbsolutePath() ) );
+
+        setVariableValueToObject( mojo, "session", legacySupport.getSession() );
+    }
+
+    public void testGetClassesNotTransitive()
+            throws Exception
+    {
+        setVariableValueToObject( mojo, "remoteRepositories", "central::default::https://repo.maven.apache.org/maven2,"
+                + "central::::https://repo.maven.apache.org/maven2," + "https://repo.maven.apache.org/maven2" );
+        mojo.setArtifact("org.apache.commons:commons-lang3:3.6");
+        setVariableValueToObject( mojo, "transitive", Boolean.FALSE );
+
+        mojo.execute();
+        return;
+    }
+
+    public void testGetClassesTransitive()

Review comment:
       Um, this does not seem to test anything except that it does not explode.
   
   
   

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,396 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver().resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver().resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();
+
+        while ( e.hasMoreElements() )
+        {
+            JarEntry entry = ( JarEntry )e.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( name.length() <= 6 || !name.substring( name.length() - 6 ).equals( ".class" )) {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );

Review comment:
       I don't think that using the log is the best delivery mechanism, but I could be confused. @elharo what do you think? Also, I have no idea how to test for log output, you'd need to mock the log somehow.

##########
File path: src/test/java/org/apache/maven/plugins/dependency/TestGetClassesMojo.java
##########
@@ -0,0 +1,88 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.LegacySupport;
+import org.apache.maven.plugin.testing.stubs.MavenProjectStub;
+import org.apache.maven.settings.Server;
+import org.apache.maven.settings.Settings;
+import org.sonatype.aether.impl.internal.SimpleLocalRepositoryManager;
+import org.sonatype.aether.util.DefaultRepositorySystemSession;
+
+import java.io.File;
+
+public class TestGetClassesMojo
+        extends AbstractDependencyMojoTestCase
+{
+    GetClassesMojo mojo;
+
+    protected void setUp()
+            throws Exception
+    {
+        // required for mojo lookups to work
+        super.setUp( "markers", false );
+
+        File testPom = new File( getBasedir(), "target/test-classes/unit/get-test/plugin-config.xml" );
+        assert testPom.exists();
+        mojo = (GetClassesMojo) lookupMojo( "get-classes", testPom );
+
+        assertNotNull( mojo );
+
+        LegacySupport legacySupport = lookup( LegacySupport.class );
+        MavenSession session = newMavenSession( new MavenProjectStub() );
+        Settings settings = session.getSettings();
+        Server server = new Server();
+        server.setId( "myserver" );
+        server.setUsername( "foo" );
+        server.setPassword( "bar" );
+        settings.addServer( server );
+        legacySupport.setSession( session );
+        DefaultRepositorySystemSession repoSession =
+                (DefaultRepositorySystemSession) legacySupport.getRepositorySession();
+        repoSession.setLocalRepositoryManager( new SimpleLocalRepositoryManager( testDir.getAbsolutePath() ) );
+
+        setVariableValueToObject( mojo, "session", legacySupport.getSession() );
+    }
+
+    public void testGetClassesNotTransitive()
+            throws Exception
+    {
+        setVariableValueToObject( mojo, "remoteRepositories", "central::default::https://repo.maven.apache.org/maven2,"
+                + "central::::https://repo.maven.apache.org/maven2," + "https://repo.maven.apache.org/maven2" );
+        mojo.setArtifact("org.apache.commons:commons-lang3:3.6");
+        setVariableValueToObject( mojo, "transitive", Boolean.FALSE );
+
+        mojo.execute();
+        return;

Review comment:
       No need for return.

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";

Review comment:
       It will work for a .war or any other 'renamed jar'. But the substitution of dots and slashes should perhaps be removed for non-.jar.

##########
File path: src/test/java/org/apache/maven/plugins/dependency/TestGetClassesMojo.java
##########
@@ -0,0 +1,86 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.LegacySupport;
+import org.apache.maven.plugin.testing.stubs.MavenProjectStub;
+import org.apache.maven.settings.Server;
+import org.apache.maven.settings.Settings;
+import org.sonatype.aether.impl.internal.SimpleLocalRepositoryManager;

Review comment:
       Do you have an example to point at here?

##########
File path: src/test/java/org/apache/maven/plugins/dependency/TestGetClassesMojo.java
##########
@@ -0,0 +1,86 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.LegacySupport;
+import org.apache.maven.plugin.testing.stubs.MavenProjectStub;
+import org.apache.maven.settings.Server;
+import org.apache.maven.settings.Settings;
+import org.sonatype.aether.impl.internal.SimpleLocalRepositoryManager;
+import org.sonatype.aether.util.DefaultRepositorySystemSession;
+
+import java.io.File;
+
+public class TestGetClassesMojo
+        extends AbstractDependencyMojoTestCase
+{
+    GetClassesMojo mojo;
+
+    protected void setUp()
+            throws Exception
+    {
+        // required for mojo lookups to work
+        super.setUp( "markers", false );
+
+        File testPom = new File( getBasedir(), "target/test-classes/unit/get-test/plugin-config.xml" );
+        assert testPom.exists();

Review comment:
       oh, whoops, sorry I missed this.




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[GitHub] [maven-dependency-plugin] jonvolfson commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r441030376



##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )

Review comment:
       fixed

##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = getDependencyResolver()
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = getArtifactResolver()
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact: " + e.getMessage(), e );
+        }
+    }
+
+    public void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration e = jarFile.entries();
+
+        while ( e.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) e.nextElement();
+            String name = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( name.length() <= 6 || !name.substring( name.length() - 6 ).equals( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            name = name.substring( 0, name.length() - 6 ).replace( '/', '.' );
+            getLog().info( name );
+        }
+        jarFile.close();
+    }
+
+    public ProjectBuildingRequest buildBuildingRequest()

Review comment:
       fixed




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[GitHub] [maven-dependency-plugin] jonvolfson commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r431270700



##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();

Review comment:
       I do not as well. This was taken from the GetMojo. It seems this class is needed in order to properly use the artifact/dependency resolver when retrieving the specified artifact as DefaultArtifactCoordinate creates new problems.




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[GitHub] [maven-dependency-plugin] jonvolfson commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r431382426



##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,391 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. That is,
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *

Review comment:
       fixed

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,391 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. That is,
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = makeBuildingRequest();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = dependencyResolver
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = artifactResolver
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact " + artifact + ": " + e.getMessage(), e );
+        }
+    }
+
+    private void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration entries = jarFile.entries();
+
+        while ( entries.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) entries.nextElement();
+            String entryName = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( !entryName.endsWith( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            String className = entryName.substring( 0, entryName.length() - 6 ).replace( '/', '.' );
+            getLog().info( className );
+        }
+        jarFile.close();

Review comment:
       fixed

##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,391 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. That is,
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = makeBuildingRequest();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = dependencyResolver
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = artifactResolver
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact " + artifact + ": " + e.getMessage(), e );
+        }
+    }
+
+    private void printClassesFromArtifactResult( ArtifactResult result )
+            throws IOException
+    {
+        JarFile jarFile = new JarFile( result.getArtifact().getFile() );
+        Enumeration entries = jarFile.entries();
+
+        while ( entries.hasMoreElements() )
+        {
+            JarEntry entry = (JarEntry) entries.nextElement();
+            String entryName = entry.getName();
+
+            // filter out files that do not end in .class
+            if ( !entryName.endsWith( ".class" ) )
+            {
+                continue;
+            }
+
+            // remove .class from the end and change format to use periods instead of forward slashes
+            String className = entryName.substring( 0, entryName.length() - 6 ).replace( '/', '.' );
+            getLog().info( className );
+        }
+        jarFile.close();
+    }
+
+    private ProjectBuildingRequest makeBuildingRequest()
+            throws MojoExecutionException, MojoFailureException
+    {
+        if ( artifact == null )
+        {
+            throw new MojoFailureException( "You must specify an artifact, "
+                    + "e.g. -Dartifact=org.apache.maven.plugins:maven-downloader-plugin:1.0" );
+        }
+        if ( artifact != null )
+        {
+            String[] tokens = artifact.split( ":" );
+            if ( tokens.length < 3 || tokens.length > 5 )
+            {
+                throw new MojoFailureException( "Invalid artifact, you must specify "
+                        + "groupId:artifactId:version[:packaging[:classifier]] " + artifact );
+            }
+            coordinate.setGroupId( tokens[0] );
+            coordinate.setArtifactId( tokens[1] );
+            coordinate.setVersion( tokens[2] );
+            if ( tokens.length >= 4 )
+            {
+                coordinate.setType( tokens[3] );
+            }
+            if ( tokens.length == 5 )
+            {
+                coordinate.setClassifier( tokens[4] );
+            }
+        }
+
+        ArtifactRepositoryPolicy always =
+                new ArtifactRepositoryPolicy( true, ArtifactRepositoryPolicy.UPDATE_POLICY_ALWAYS,
+                        ArtifactRepositoryPolicy.CHECKSUM_POLICY_WARN );
+
+        List<ArtifactRepository> repoList = new ArrayList<>();
+
+        if ( pomRemoteRepositories != null )
+        {
+            repoList.addAll( pomRemoteRepositories );
+        }
+
+        if ( remoteRepositories != null )
+        {
+            // Use the same format as in the deploy plugin id::layout::url
+            String[] repos = remoteRepositories.split( "," );
+            for ( String repo : repos )
+            {
+                repoList.add( parseRepository( repo, always ) );
+            }
+        }
+
+        ProjectBuildingRequest buildingRequest =
+                new DefaultProjectBuildingRequest( session.getProjectBuildingRequest() );
+
+        Settings settings = session.getSettings();
+        repositorySystem.injectMirror( repoList, settings.getMirrors() );
+        repositorySystem.injectProxy( repoList, settings.getProxies() );
+        repositorySystem.injectAuthentication( repoList, settings.getServers() );
+
+        buildingRequest.setRemoteRepositories( repoList );
+
+        return buildingRequest;
+    }
+
+    protected ArtifactCoordinate toArtifactCoordinate( DependableCoordinate dependableCoordinate )
+    {
+        ArtifactHandler artifactHandler = artifactHandlerManager.getArtifactHandler( dependableCoordinate.getType() );
+        DefaultArtifactCoordinate artifactCoordinate = new DefaultArtifactCoordinate();
+        artifactCoordinate.setGroupId( dependableCoordinate.getGroupId() );
+        artifactCoordinate.setArtifactId( dependableCoordinate.getArtifactId() );
+        artifactCoordinate.setVersion( dependableCoordinate.getVersion() );
+        artifactCoordinate.setClassifier( dependableCoordinate.getClassifier() );
+        artifactCoordinate.setExtension( artifactHandler.getExtension() );
+        return artifactCoordinate;
+    }
+
+    ArtifactRepository parseRepository( String repo, ArtifactRepositoryPolicy policy )
+            throws MojoFailureException
+    {
+        // if it's a simple url
+        String id = "temp";
+        ArtifactRepositoryLayout layout = getLayout( "default" );
+
+        // if it's an extended repo URL of the form id::layout::url
+        if ( repo.contains( "::" ) )
+        {
+            Matcher matcher = ALT_REPO_SYNTAX_PATTERN.matcher( repo );
+            if ( !matcher.matches() )
+            {
+                throw new MojoFailureException( repo, "Invalid syntax for repository: " + repo,
+                        "Invalid syntax for repository. Use \"id::layout::url\" or \"URL\"." );
+            }
+
+            id = matcher.group( 1 ).trim();
+            if ( !( matcher.group( 2 ) == null || matcher.group( 2 ).trim().isEmpty() ) )
+            {
+                layout = getLayout( matcher.group( 2 ).trim() );
+            }
+            repo = matcher.group( 3 ).trim();
+        }
+        return new MavenArtifactRepository( id, repo, layout, policy, policy );
+    }
+
+    private ArtifactRepositoryLayout getLayout( String id )
+            throws MojoFailureException
+    {
+        ArtifactRepositoryLayout layout = repositoryLayouts.get( id );
+
+        if ( layout == null )
+        {
+            throw new MojoFailureException( id, "Invalid repository layout", "Invalid repository layout: " + id );
+        }
+
+        return layout;
+    }
+
+    /**
+     * @return {@link #skip}

Review comment:
       fixed

##########
File path: src/test/java/org/apache/maven/plugins/dependency/TestGetClassesMojo.java
##########
@@ -0,0 +1,87 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.LegacySupport;
+import org.apache.maven.plugin.testing.stubs.MavenProjectStub;
+import org.apache.maven.settings.Server;
+import org.apache.maven.settings.Settings;
+import org.junit.Assert;
+import org.sonatype.aether.impl.internal.SimpleLocalRepositoryManager;
+import org.sonatype.aether.util.DefaultRepositorySystemSession;
+
+import java.io.File;
+
+public class TestGetClassesMojo
+        extends AbstractDependencyMojoTestCase
+{
+    ListClassesMojo mojo;

Review comment:
       fixed




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[GitHub] [maven-dependency-plugin] jonvolfson commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r441029746



##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "true" )
+    private boolean transitive = true;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     * @since 2.7
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();
+
+        try
+        {
+            getLog().info( "Retrieving classes of dependencies for " + artifact );

Review comment:
       fixed, forgot to comment




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[GitHub] [maven-dependency-plugin] jonvolfson commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r441029129



##########
File path: src/main/java/org/apache/maven/plugins/dependency/GetClassesMojo.java
##########
@@ -0,0 +1,406 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+import org.codehaus.plexus.util.StringUtils;
+
+
+/**
+ * Retrieves and lists all class dependencies for the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "get-classes", requiresProject = false, threadSafe = true )
+public class GetClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The groupId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifactId of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just url, separated by comma. ie.

Review comment:
       fixed, forgot to comment




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[GitHub] [maven-dependency-plugin] jonvolfson commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r431277735



##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,402 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. ie.
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = buildBuildingRequest();
+        DefaultDependableCoordinate coordinate = getCoordinate();

Review comment:
       fixed




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[GitHub] [maven-dependency-plugin] jonvolfson commented on pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#issuecomment-634103391


   Updated PR title. This is a fix for MDEP-645


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[GitHub] [maven-dependency-plugin] jonvolfson commented on a change in pull request #57: [MDEP-645] Created new mojo GetClassesMojo which lists all class dependencies for a specified artifact.

Posted by GitBox <gi...@apache.org>.

jonvolfson commented on a change in pull request #57:
URL: https://github.com/apache/maven-dependency-plugin/pull/57#discussion_r431379203



##########
File path: src/main/java/org/apache/maven/plugins/dependency/ListClassesMojo.java
##########
@@ -0,0 +1,391 @@
+package org.apache.maven.plugins.dependency;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.maven.artifact.handler.ArtifactHandler;
+import org.apache.maven.artifact.handler.manager.ArtifactHandlerManager;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
+import org.apache.maven.artifact.repository.MavenArtifactRepository;
+import org.apache.maven.artifact.repository.layout.ArtifactRepositoryLayout;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.DefaultProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.repository.RepositorySystem;
+import org.apache.maven.settings.Settings;
+import org.apache.maven.shared.transfer.artifact.ArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.DefaultArtifactCoordinate;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolver;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResolverException;
+import org.apache.maven.shared.transfer.artifact.resolve.ArtifactResult;
+import org.apache.maven.shared.transfer.dependencies.DefaultDependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.DependableCoordinate;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolver;
+import org.apache.maven.shared.transfer.dependencies.resolve.DependencyResolverException;
+
+
+/**
+ * Retrieves and lists all classes contained in the specified artifact from the specified remote repositories.
+ */
+@Mojo( name = "list-classes", requiresProject = false, threadSafe = true )
+public class ListClassesMojo
+    extends AbstractMojo
+{
+    private static final Pattern ALT_REPO_SYNTAX_PATTERN = Pattern.compile( "(.+)::(.*)::(.+)" );
+
+    @Parameter( defaultValue = "${session}", required = true, readonly = true )
+    private MavenSession session;
+
+    @Component
+    private ArtifactResolver artifactResolver;
+
+    @Component
+    private DependencyResolver dependencyResolver;
+
+    @Component
+    private ArtifactHandlerManager artifactHandlerManager;
+
+    /**
+     * Map that contains the layouts.
+     */
+    @Component( role = ArtifactRepositoryLayout.class )
+    private Map<String, ArtifactRepositoryLayout> repositoryLayouts;
+
+    /**
+     * The repository system.
+     */
+    @Component
+    private RepositorySystem repositorySystem;
+
+    private DefaultDependableCoordinate coordinate = new DefaultDependableCoordinate();
+
+    /**
+     * The group ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "groupId" )
+    private String groupId;
+
+    /**
+     * The artifact ID of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "artifactId" )
+    private String artifactId;
+
+    /**
+     * The version of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "version" )
+    private String version;
+
+    /**
+     * The classifier of the artifact to download. Ignored if {@link #artifact} is used.
+     *
+     * @since 2.3
+     */
+    @Parameter( property = "classifier" )
+    private String classifier;
+
+    /**
+     * The packaging of the artifact to download. Ignored if {@link #artifact} is used.
+     */
+    @Parameter( property = "packaging", defaultValue = "jar" )
+    private String packaging = "jar";
+
+    /**
+     * Repositories in the format id::[layout]::url or just URLs, separated by comma. That is,
+     * central::default::https://repo.maven.apache.org/maven2,myrepo::::https://repo.acme.com,https://repo.acme2.com
+     */
+    @Parameter( property = "remoteRepositories" )
+    private String remoteRepositories;
+
+    /**
+     * A string of the form groupId:artifactId:version[:packaging[:classifier]].
+     */
+    @Parameter( property = "artifact" )
+    private String artifact;
+
+    @Parameter( defaultValue = "${project.remoteArtifactRepositories}", readonly = true, required = true )
+    private List<ArtifactRepository> pomRemoteRepositories;
+
+    /**
+     * Download transitively, retrieving the specified artifact and all of its dependencies.
+     */
+    @Parameter( property = "transitive", defaultValue = "false" )
+    private boolean transitive = false;
+
+    /**
+     * Skip plugin execution completely.
+     *
+     */
+    @Parameter( property = "mdep.skip", defaultValue = "false" )
+    private boolean skip;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException
+    {
+        ProjectBuildingRequest buildingRequest = makeBuildingRequest();
+
+        try
+        {
+            if ( isTransitive() )
+            {
+                Iterable<ArtifactResult> artifacts = dependencyResolver
+                        .resolveDependencies( buildingRequest, coordinate, null );
+
+                for ( ArtifactResult result : artifacts )
+                {
+                    printClassesFromArtifactResult( result );
+                }
+            }
+            else
+            {
+                ArtifactResult result = artifactResolver
+                        .resolveArtifact( buildingRequest, toArtifactCoordinate( coordinate ) );
+
+                printClassesFromArtifactResult( result );
+            }
+        }
+        catch ( ArtifactResolverException | DependencyResolverException | IOException e )
+        {
+            throw new MojoExecutionException( "Couldn't download artifact " + artifact + ": " + e.getMessage(), e );

Review comment:
       I believe the original message was correct before I changed it to include artifact. If a transitive dependency wasn't able to be resolved, e.getMessage() should have included the correct one.




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