You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@maven.apache.org by GitBox <gi...@apache.org> on 2020/05/27 03:28:46 UTC

[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.

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




----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
users@infra.apache.org