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Posted to commits@maven.apache.org by mi...@apache.org on 2017/05/11 21:05:54 UTC

[2/2] maven-resolver git commit: [MRESOLVER-4] Use java.util.Objects#requireNonNull to intercept invalid input

[MRESOLVER-4] Use java.util.Objects#requireNonNull to intercept invalid input


Project: http://git-wip-us.apache.org/repos/asf/maven-resolver/repo
Commit: http://git-wip-us.apache.org/repos/asf/maven-resolver/commit/362ce50e
Tree: http://git-wip-us.apache.org/repos/asf/maven-resolver/tree/362ce50e
Diff: http://git-wip-us.apache.org/repos/asf/maven-resolver/diff/362ce50e

Branch: refs/heads/MRESOLVER-4
Commit: 362ce50e1fb3dc4a7e1eda65318d4ba6d9f0683f
Parents: 5fae685
Author: Michael Osipov <mi...@apache.org>
Authored: Mon Nov 7 22:06:19 2016 +0100
Committer: Michael Osipov <mi...@apache.org>
Committed: Thu May 11 23:04:10 2017 +0200

----------------------------------------------------------------------
 .../aether/DefaultRepositorySystemSession.java  |   8 +-
 .../org/eclipse/aether/DefaultSessionData.java  |  17 +--
 .../org/eclipse/aether/RepositoryEvent.java     |  17 +--
 .../aether/artifact/DefaultArtifactType.java    |  13 +-
 .../aether/collection/CollectResult.java        |  11 +-
 .../eclipse/aether/deployment/DeployResult.java |  11 +-
 .../aether/graph/DefaultDependencyNode.java     |   6 +-
 .../org/eclipse/aether/graph/Dependency.java    |   7 +-
 .../aether/installation/InstallResult.java      |  11 +-
 .../aether/metadata/DefaultMetadata.java        |   7 +-
 .../repository/AuthenticationContext.java       |  21 ++--
 .../aether/repository/LocalArtifactResult.java  |  13 +-
 .../aether/repository/LocalMetadataResult.java  |  13 +-
 .../aether/repository/RemoteRepository.java     |  11 +-
 .../resolution/ArtifactDescriptorResult.java    |   9 +-
 .../aether/resolution/ArtifactResult.java       |  11 +-
 .../aether/resolution/DependencyResult.java     |   9 +-
 .../aether/resolution/MetadataResult.java       |  12 +-
 .../aether/resolution/VersionRangeResult.java   |   9 +-
 .../aether/resolution/VersionResult.java        |  11 +-
 .../eclipse/aether/transfer/TransferEvent.java  |  41 ++-----
 .../eclipse/aether/version/VersionRange.java    |  12 +-
 .../repository/RemoteRepositoryBuilderTest.java |   2 +-
 .../basic/BasicRepositoryConnector.java         |  13 +-
 .../basic/BasicRepositoryConnectorFactory.java  |  34 ++---
 .../aether/impl/DefaultServiceLocator.java      |  25 +---
 .../internal/impl/DefaultArtifactResolver.java  |  49 ++------
 .../impl/DefaultDependencyCollector.java        |  19 +--
 ...ultDependencyGraphTransformationContext.java |  12 +-
 .../aether/internal/impl/DefaultDeployer.java   |  49 ++------
 .../aether/internal/impl/DefaultInstaller.java  |  25 +---
 .../impl/DefaultLocalRepositoryProvider.java    |   7 +-
 .../internal/impl/DefaultMetadataResolver.java  |  37 ++----
 .../impl/DefaultRemoteRepositoryManager.java    |  13 +-
 .../DefaultRepositoryConnectorProvider.java     |  12 +-
 .../impl/DefaultRepositoryEventDispatcher.java  |   7 +-
 .../impl/DefaultRepositoryLayoutProvider.java   |  12 +-
 .../internal/impl/DefaultRepositorySystem.java  | 123 ++++---------------
 .../impl/DefaultTransporterProvider.java        |  12 +-
 .../impl/DefaultUpdateCheckManager.java         |  19 +--
 .../impl/EnhancedLocalRepositoryManager.java    |   7 +-
 .../impl/SimpleLocalRepositoryManager.java      |   6 +-
 .../impl/DefaultDependencyCollectorTest.java    |   4 +-
 .../impl/DefaultUpdateCheckManagerTest.java     |   2 +-
 .../spi/connector/layout/RepositoryLayout.java  |  11 +-
 .../spi/connector/transport/TransportTask.java  |  11 +-
 .../test/util/DependencyGraphParser.java        |   2 +-
 ...estDependencyGraphTransformationContext.java |  12 +-
 .../test/util/TestVersionConstraint.java        |  18 +--
 .../wagon/PlexusWagonConfigurator.java          |  10 +-
 .../transport/wagon/PlexusWagonProvider.java    |  10 +-
 .../util/artifact/DelegatingArtifact.java       |  11 +-
 .../aether/util/artifact/SubArtifact.java       |   7 +-
 .../concurrency/RunnableErrorForwarder.java     |   9 +-
 .../aether/util/filter/NotDependencyFilter.java |   9 +-
 .../graph/transformer/ConflictResolver.java     |  25 +---
 .../visitor/FilteringDependencyVisitor.java     |  10 +-
 .../graph/visitor/TreeDependencyVisitor.java    |   9 +-
 .../repository/ComponentAuthentication.java     |   7 +-
 .../ConservativeAuthenticationSelector.java     |  10 +-
 .../repository/ConservativeProxySelector.java   |  10 +-
 .../util/repository/DefaultProxySelector.java   |  24 +++-
 .../util/repository/SecretAuthentication.java   |   7 +-
 .../util/repository/StringAuthentication.java   |   7 +-
 .../util/version/GenericVersionConstraint.java  |  18 +--
 .../aether/util/artifact/SubArtifactTest.java   |   2 +-
 .../transformer/JavaScopeSelectorTest.java      |   4 +-
 67 files changed, 310 insertions(+), 702 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultRepositorySystemSession.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultRepositorySystemSession.java b/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultRepositorySystemSession.java
index 93ebaca..13773df 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultRepositorySystemSession.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultRepositorySystemSession.java
@@ -22,6 +22,7 @@ package org.eclipse.aether;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.artifact.ArtifactType;
 import org.eclipse.aether.artifact.ArtifactTypeRegistry;
@@ -137,15 +138,12 @@ public final class DefaultRepositorySystemSession
      * system/user/config properties are copied as well. In other words, invoking any mutator on the new session itself
      * has no effect on the original session. Other mutable objects like the session data and cache (if any) are not
      * copied and will be shared with the original session unless reconfigured.
-     * 
+     *
      * @param session The session to copy, must not be {@code null}.
      */
     public DefaultRepositorySystemSession( RepositorySystemSession session )
     {
-        if ( session == null )
-        {
-            throw new IllegalArgumentException( "repository system session not specified" );
-        }
+        requireNonNull( session, "repository system session cannot be null" );
 
         setOffline( session.isOffline() );
         setIgnoreArtifactDescriptorRepositories( session.isIgnoreArtifactDescriptorRepositories() );

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultSessionData.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultSessionData.java b/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultSessionData.java
index e78df3a..3c2a76e 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultSessionData.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultSessionData.java
@@ -19,6 +19,8 @@ package org.eclipse.aether;
  * under the License.
  */
 
+import static java.util.Objects.requireNonNull;
+
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 
@@ -38,10 +40,7 @@ public final class DefaultSessionData
 
     public void set( Object key, Object value )
     {
-        if ( key == null )
-        {
-            throw new IllegalArgumentException( "key must not be null" );
-        }
+        requireNonNull( key, "key cannot be null" );
 
         if ( value != null )
         {
@@ -55,10 +54,7 @@ public final class DefaultSessionData
 
     public boolean set( Object key, Object oldValue, Object newValue )
     {
-        if ( key == null )
-        {
-            throw new IllegalArgumentException( "key must not be null" );
-        }
+        requireNonNull( key, "key cannot be null" );
 
         if ( newValue != null )
         {
@@ -80,10 +76,7 @@ public final class DefaultSessionData
 
     public Object get( Object key )
     {
-        if ( key == null )
-        {
-            throw new IllegalArgumentException( "key must not be null" );
-        }
+        requireNonNull( key, "key cannot be null" );
 
         return data.get( key );
     }

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/RepositoryEvent.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/RepositoryEvent.java b/maven-resolver-api/src/main/java/org/eclipse/aether/RepositoryEvent.java
index 33816ba..812ef7d 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/RepositoryEvent.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/RepositoryEvent.java
@@ -22,6 +22,7 @@ package org.eclipse.aether;
 import java.io.File;
 import java.util.Collections;
 import java.util.List;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.artifact.Artifact;
 import org.eclipse.aether.metadata.Metadata;
@@ -310,27 +311,19 @@ public final class RepositoryEvent
 
         /**
          * Creates a new event builder for the specified session and event type.
-         * 
+         *
          * @param session The repository system session, must not be {@code null}.
          * @param type The type of the event, must not be {@code null}.
          */
         public Builder( RepositorySystemSession session, EventType type )
         {
-            if ( session == null )
-            {
-                throw new IllegalArgumentException( "session not specified" );
-            }
-            this.session = session;
-            if ( type == null )
-            {
-                throw new IllegalArgumentException( "event type not specified" );
-            }
-            this.type = type;
+            this.session = requireNonNull( session, "session cannot be null" );
+            this.type = requireNonNull( type, "event type cannot be null" );
         }
 
         /**
          * Sets the artifact involved in the event.
-         * 
+         *
          * @param artifact The involved artifact, may be {@code null}.
          * @return This event builder for chaining, never {@code null}.
          */

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/artifact/DefaultArtifactType.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/artifact/DefaultArtifactType.java b/maven-resolver-api/src/main/java/org/eclipse/aether/artifact/DefaultArtifactType.java
index c0d2ad8..5ae6daa 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/artifact/DefaultArtifactType.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/artifact/DefaultArtifactType.java
@@ -22,6 +22,7 @@ package org.eclipse.aether.artifact;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
+import static java.util.Objects.requireNonNull;
 
 /**
  * A simple artifact type.
@@ -83,11 +84,11 @@ public final class DefaultArtifactType
     public DefaultArtifactType( String id, String extension, String classifier, String language,
                                 boolean constitutesBuildPath, boolean includesDependencies )
     {
-        if ( id == null || id.length() < 0 )
+        this.id = requireNonNull( id, "type id cannot be null" );
+        if ( id.length() == 0 )
         {
-            throw new IllegalArgumentException( "no type id specified" );
+            throw new IllegalArgumentException( "type id cannot be empty" );
         }
-        this.id = id;
         this.extension = emptify( extension );
         this.classifier = emptify( classifier );
         Map<String, String> props = new HashMap<String, String>();
@@ -108,11 +109,11 @@ public final class DefaultArtifactType
      */
     public DefaultArtifactType( String id, String extension, String classifier, Map<String, String> properties )
     {
-        if ( id == null || id.length() < 0 )
+        this.id = requireNonNull( id, "type id cannot be null" );
+        if ( id.length() == 0 )
         {
-            throw new IllegalArgumentException( "no type id specified" );
+            throw new IllegalArgumentException( "type id cannot be empty" );
         }
-        this.id = id;
         this.extension = emptify( extension );
         this.classifier = emptify( classifier );
         this.properties = AbstractArtifact.copyProperties( properties );

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/collection/CollectResult.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/collection/CollectResult.java b/maven-resolver-api/src/main/java/org/eclipse/aether/collection/CollectResult.java
index dd9f02e..53ebae4 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/collection/CollectResult.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/collection/CollectResult.java
@@ -22,6 +22,7 @@ package org.eclipse.aether.collection;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.RepositorySystem;
 import org.eclipse.aether.RepositorySystemSession;
@@ -46,23 +47,19 @@ public final class CollectResult
 
     /**
      * Creates a new result for the specified request.
-     * 
+     *
      * @param request The resolution request, must not be {@code null}.
      */
     public CollectResult( CollectRequest request )
     {
-        if ( request == null )
-        {
-            throw new IllegalArgumentException( "dependency collection request has not been specified" );
-        }
-        this.request = request;
+        this.request = requireNonNull( request, "dependency collection request cannot be null" );
         exceptions = Collections.emptyList();
         cycles = Collections.emptyList();
     }
 
     /**
      * Gets the collection request that was made.
-     * 
+     *
      * @return The collection request, never {@code null}.
      */
     public CollectRequest getRequest()

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/deployment/DeployResult.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/deployment/DeployResult.java b/maven-resolver-api/src/main/java/org/eclipse/aether/deployment/DeployResult.java
index f75705e..823f671 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/deployment/DeployResult.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/deployment/DeployResult.java
@@ -22,6 +22,7 @@ package org.eclipse.aether.deployment;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.RepositorySystem;
 import org.eclipse.aether.RepositorySystemSession;
@@ -44,23 +45,19 @@ public final class DeployResult
 
     /**
      * Creates a new result for the specified request.
-     * 
+     *
      * @param request The deployment request, must not be {@code null}.
      */
     public DeployResult( DeployRequest request )
     {
-        if ( request == null )
-        {
-            throw new IllegalArgumentException( "deploy request has not been specified" );
-        }
-        this.request = request;
+        this.request = requireNonNull( request, "deploy request cannot be null" );
         artifacts = Collections.emptyList();
         metadata = Collections.emptyList();
     }
 
     /**
      * Gets the deploy request that was made.
-     * 
+     *
      * @return The deploy request, never {@code null}.
      */
     public DeployRequest getRequest()

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/graph/DefaultDependencyNode.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/graph/DefaultDependencyNode.java b/maven-resolver-api/src/main/java/org/eclipse/aether/graph/DefaultDependencyNode.java
index 66a60c6..db29fb7 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/graph/DefaultDependencyNode.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/graph/DefaultDependencyNode.java
@@ -25,6 +25,7 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.artifact.Artifact;
 import org.eclipse.aether.repository.RemoteRepository;
@@ -311,10 +312,7 @@ public final class DefaultDependencyNode
 
     public void setData( Object key, Object value )
     {
-        if ( key == null )
-        {
-            throw new IllegalArgumentException( "key must not be null" );
-        }
+        requireNonNull( key, "key cannot be null" );
 
         if ( value == null )
         {

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/graph/Dependency.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/graph/Dependency.java b/maven-resolver-api/src/main/java/org/eclipse/aether/graph/Dependency.java
index b9e7cb4..2e1a78b 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/graph/Dependency.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/graph/Dependency.java
@@ -25,6 +25,7 @@ import java.util.Collections;
 import java.util.Iterator;
 import java.util.LinkedHashSet;
 import java.util.NoSuchElementException;
+import static java.util.Objects.requireNonNull;
 import java.util.Set;
 
 import org.eclipse.aether.artifact.Artifact;
@@ -83,11 +84,7 @@ public final class Dependency
     private Dependency( Artifact artifact, String scope, Set<Exclusion> exclusions, Boolean optional )
     {
         // NOTE: This constructor assumes immutability of the provided exclusion collection, for internal use only
-        if ( artifact == null )
-        {
-            throw new IllegalArgumentException( "no artifact specified for dependency" );
-        }
-        this.artifact = artifact;
+        this.artifact = requireNonNull( artifact, "artifact cannot be null" );
         this.scope = ( scope != null ) ? scope : "";
         this.optional = optional;
         this.exclusions = exclusions;

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/installation/InstallResult.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/installation/InstallResult.java b/maven-resolver-api/src/main/java/org/eclipse/aether/installation/InstallResult.java
index 6624585..2f79023 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/installation/InstallResult.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/installation/InstallResult.java
@@ -22,6 +22,7 @@ package org.eclipse.aether.installation;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.RepositorySystem;
 import org.eclipse.aether.RepositorySystemSession;
@@ -44,23 +45,19 @@ public final class InstallResult
 
     /**
      * Creates a new result for the specified request.
-     * 
+     *
      * @param request The installation request, must not be {@code null}.
      */
     public InstallResult( InstallRequest request )
     {
-        if ( request == null )
-        {
-            throw new IllegalArgumentException( "install request has not been specified" );
-        }
-        this.request = request;
+        this.request = requireNonNull( request, "install request cannot be null" );
         artifacts = Collections.emptyList();
         metadata = Collections.emptyList();
     }
 
     /**
      * Gets the install request that was made.
-     * 
+     *
      * @return The install request, never {@code null}.
      */
     public InstallRequest getRequest()

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/metadata/DefaultMetadata.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/metadata/DefaultMetadata.java b/maven-resolver-api/src/main/java/org/eclipse/aether/metadata/DefaultMetadata.java
index 1efbb72..16bcd61 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/metadata/DefaultMetadata.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/metadata/DefaultMetadata.java
@@ -21,6 +21,7 @@ package org.eclipse.aether.metadata;
 
 import java.io.File;
 import java.util.Map;
+import static java.util.Objects.requireNonNull;
 
 /**
  * A basic metadata instance. <em>Note:</em> Instances of this class are immutable and the exposed mutators return new
@@ -127,11 +128,7 @@ public final class DefaultMetadata
         this.artifactId = emptify( artifactId );
         this.version = emptify( version );
         this.type = emptify( type );
-        if ( nature == null )
-        {
-            throw new IllegalArgumentException( "metadata nature was not specified" );
-        }
-        this.nature = nature;
+        this.nature = requireNonNull( nature, "metadata nature cannot be null" );
         this.file = file;
         this.properties = copyProperties( properties );
     }

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/repository/AuthenticationContext.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/repository/AuthenticationContext.java b/maven-resolver-api/src/main/java/org/eclipse/aether/repository/AuthenticationContext.java
index bd248a0..93bcdce 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/repository/AuthenticationContext.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/repository/AuthenticationContext.java
@@ -24,6 +24,7 @@ import java.io.File;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.RepositorySystemSession;
 
@@ -179,11 +180,7 @@ public final class AuthenticationContext
     private AuthenticationContext( RepositorySystemSession session, RemoteRepository repository, Proxy proxy,
                                    Authentication auth )
     {
-        if ( session == null )
-        {
-            throw new IllegalArgumentException( "repository system session missing" );
-        }
-        this.session = session;
+        this.session = requireNonNull( session, "repository system session cannot be null" );
         this.repository = repository;
         this.proxy = proxy;
         this.auth = auth;
@@ -257,10 +254,12 @@ public final class AuthenticationContext
      */
     public <T> T get( String key, Map<String, String> data, Class<T> type )
     {
-        if ( key == null )
+        requireNonNull( key, "authentication key cannot be null" );
+        if ( key.length() == 0 )
         {
-            throw new IllegalArgumentException( "authentication data key missing" );
+            throw new IllegalArgumentException( "authentication key cannot be empty" );
         }
+
         Object value;
         synchronized ( authData )
         {
@@ -333,16 +332,18 @@ public final class AuthenticationContext
      * Puts the specified authentication data into this context. This method should only be called from implementors of
      * {@link Authentication#fill(AuthenticationContext, String, Map)}. Passed in character arrays are not cloned and
      * become owned by this context, i.e. get erased when the context gets closed.
-     * 
+     *
      * @param key The key to associate the authentication data with, must not be {@code null}.
      * @param value The (cleartext) authentication data to store, may be {@code null}.
      */
     public void put( String key, Object value )
     {
-        if ( key == null )
+        requireNonNull( key, "authentication key cannot be null" );
+        if ( key.length() == 0 )
         {
-            throw new IllegalArgumentException( "authentication data key missing" );
+            throw new IllegalArgumentException( "authentication key cannot be empty" );
         }
+
         synchronized ( authData )
         {
             Object oldValue = authData.put( key, value );

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/repository/LocalArtifactResult.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/repository/LocalArtifactResult.java b/maven-resolver-api/src/main/java/org/eclipse/aether/repository/LocalArtifactResult.java
index e611b27..34dbe0a 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/repository/LocalArtifactResult.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/repository/LocalArtifactResult.java
@@ -20,12 +20,13 @@ package org.eclipse.aether.repository;
  */
 
 import java.io.File;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.RepositorySystemSession;
 
 /**
  * A result from the local repository about the existence of an artifact.
- * 
+ *
  * @see LocalRepositoryManager#find(RepositorySystemSession, LocalArtifactRequest)
  */
 public final class LocalArtifactResult
@@ -41,21 +42,17 @@ public final class LocalArtifactResult
 
     /**
      * Creates a new result for the specified request.
-     * 
+     *
      * @param request The local artifact request, must not be {@code null}.
      */
     public LocalArtifactResult( LocalArtifactRequest request )
     {
-        if ( request == null )
-        {
-            throw new IllegalArgumentException( "local artifact request has not been specified" );
-        }
-        this.request = request;
+        this.request = requireNonNull( request, "local artifact request cannot be null" );
     }
 
     /**
      * Gets the request corresponding to this result.
-     * 
+     *
      * @return The corresponding request, never {@code null}.
      */
     public LocalArtifactRequest getRequest()

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/repository/LocalMetadataResult.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/repository/LocalMetadataResult.java b/maven-resolver-api/src/main/java/org/eclipse/aether/repository/LocalMetadataResult.java
index 29bd045..12f3a35 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/repository/LocalMetadataResult.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/repository/LocalMetadataResult.java
@@ -20,12 +20,13 @@ package org.eclipse.aether.repository;
  */
 
 import java.io.File;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.RepositorySystemSession;
 
 /**
  * A result from the local repository about the existence of metadata.
- * 
+ *
  * @see LocalRepositoryManager#find(RepositorySystemSession, LocalMetadataRequest)
  */
 public final class LocalMetadataResult
@@ -39,21 +40,17 @@ public final class LocalMetadataResult
 
     /**
      * Creates a new result for the specified request.
-     * 
+     *
      * @param request The local metadata request, must not be {@code null}.
      */
     public LocalMetadataResult( LocalMetadataRequest request )
     {
-        if ( request == null )
-        {
-            throw new IllegalArgumentException( "local metadata request has not been specified" );
-        }
-        this.request = request;
+        this.request = requireNonNull( request, "local metadata request cannot be null" );
     }
 
     /**
      * Gets the request corresponding to this result.
-     * 
+     *
      * @return The corresponding request, never {@code null}.
      */
     public LocalMetadataRequest getRequest()

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/repository/RemoteRepository.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/repository/RemoteRepository.java b/maven-resolver-api/src/main/java/org/eclipse/aether/repository/RemoteRepository.java
index 31259ca..f854051 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/repository/RemoteRepository.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/repository/RemoteRepository.java
@@ -23,6 +23,7 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import static java.util.Objects.requireNonNull;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -335,22 +336,18 @@ public final class RemoteRepository
          * Creates a new repository builder which uses the specified remote repository as a prototype for the new one.
          * All properties which have not been set on the builder will be copied from the prototype when building the
          * repository.
-         * 
+         *
          * @param prototype The remote repository to use as prototype, must not be {@code null}.
          */
         public Builder( RemoteRepository prototype )
         {
-            if ( prototype == null )
-            {
-                throw new IllegalArgumentException( "repository prototype missing" );
-            }
-            this.prototype = prototype;
+            this.prototype = requireNonNull( prototype, "remote repository prototype cannot be null" );
         }
 
         /**
          * Builds a new remote repository from the current values of this builder. The state of the builder itself
          * remains unchanged.
-         * 
+         *
          * @return The remote repository, never {@code null}.
          */
         public RemoteRepository build()

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/ArtifactDescriptorResult.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/ArtifactDescriptorResult.java b/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/ArtifactDescriptorResult.java
index 4c53b6e..3d0edd2 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/ArtifactDescriptorResult.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/ArtifactDescriptorResult.java
@@ -24,6 +24,7 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.RepositorySystem;
 import org.eclipse.aether.RepositorySystemSession;
@@ -62,16 +63,12 @@ public final class ArtifactDescriptorResult
 
     /**
      * Creates a new result for the specified request.
-     * 
+     *
      * @param request The descriptor request, must not be {@code null}.
      */
     public ArtifactDescriptorResult( ArtifactDescriptorRequest request )
     {
-        if ( request == null )
-        {
-            throw new IllegalArgumentException( "artifact descriptor request has not been specified" );
-        }
-        this.request = request;
+        this.request = requireNonNull( request, "artifact descriptor request cannot be null" );
         artifact = request.getArtifact();
         exceptions = Collections.emptyList();
         relocations = Collections.emptyList();

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/ArtifactResult.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/ArtifactResult.java b/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/ArtifactResult.java
index 5ae820b..5057855 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/ArtifactResult.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/ArtifactResult.java
@@ -22,6 +22,7 @@ package org.eclipse.aether.resolution;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.RepositorySystem;
 import org.eclipse.aether.RepositorySystemSession;
@@ -48,22 +49,18 @@ public final class ArtifactResult
 
     /**
      * Creates a new result for the specified request.
-     * 
+     *
      * @param request The resolution request, must not be {@code null}.
      */
     public ArtifactResult( ArtifactRequest request )
     {
-        if ( request == null )
-        {
-            throw new IllegalArgumentException( "resolution request has not been specified" );
-        }
-        this.request = request;
+        this.request = requireNonNull( request, "artifact request cannot be null" );
         exceptions = Collections.emptyList();
     }
 
     /**
      * Gets the resolution request that was made.
-     * 
+     *
      * @return The resolution request, never {@code null}.
      */
     public ArtifactRequest getRequest()

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/DependencyResult.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/DependencyResult.java b/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/DependencyResult.java
index 030e923..8ba8646 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/DependencyResult.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/DependencyResult.java
@@ -21,6 +21,7 @@ package org.eclipse.aether.resolution;
 
 import java.util.Collections;
 import java.util.List;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.RepositorySystem;
 import org.eclipse.aether.RepositorySystemSession;
@@ -47,16 +48,12 @@ public final class DependencyResult
 
     /**
      * Creates a new result for the specified request.
-     * 
+     *
      * @param request The resolution request, must not be {@code null}.
      */
     public DependencyResult( DependencyRequest request )
     {
-        if ( request == null )
-        {
-            throw new IllegalArgumentException( "dependency request has not been specified" );
-        }
-        this.request = request;
+        this.request = requireNonNull( request, "dependency request cannot be null" );
         root = request.getRoot();
         cycles = Collections.emptyList();
         collectExceptions = Collections.emptyList();

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/MetadataResult.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/MetadataResult.java b/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/MetadataResult.java
index 2bba499..cedd395 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/MetadataResult.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/MetadataResult.java
@@ -19,6 +19,8 @@ package org.eclipse.aether.resolution;
  * under the License.
  */
 
+import static java.util.Objects.requireNonNull;
+
 import org.eclipse.aether.RepositorySystem;
 import org.eclipse.aether.RepositorySystemSession;
 import org.eclipse.aether.metadata.Metadata;
@@ -42,21 +44,17 @@ public final class MetadataResult
 
     /**
      * Creates a new result for the specified request.
-     * 
+     *
      * @param request The resolution request, must not be {@code null}.
      */
     public MetadataResult( MetadataRequest request )
     {
-        if ( request == null )
-        {
-            throw new IllegalArgumentException( "metadata request has not been specified" );
-        }
-        this.request = request;
+        this.request = requireNonNull( request, "metadata request cannot be null" );
     }
 
     /**
      * Gets the resolution request that was made.
-     * 
+     *
      * @return The resolution request, never {@code null}.
      */
     public MetadataRequest getRequest()

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/VersionRangeResult.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/VersionRangeResult.java b/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/VersionRangeResult.java
index 4749f7c..8af78ea 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/VersionRangeResult.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/VersionRangeResult.java
@@ -24,6 +24,7 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.RepositorySystem;
 import org.eclipse.aether.RepositorySystemSession;
@@ -51,16 +52,12 @@ public final class VersionRangeResult
 
     /**
      * Creates a new result for the specified request.
-     * 
+     *
      * @param request The resolution request, must not be {@code null}.
      */
     public VersionRangeResult( VersionRangeRequest request )
     {
-        if ( request == null )
-        {
-            throw new IllegalArgumentException( "version range request has not been specified" );
-        }
-        this.request = request;
+        this.request = requireNonNull( request, "version range request cannot be null" );
         exceptions = Collections.emptyList();
         versions = Collections.emptyList();
         repositories = Collections.emptyMap();

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/VersionResult.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/VersionResult.java b/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/VersionResult.java
index 5125773..486a287 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/VersionResult.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/resolution/VersionResult.java
@@ -22,6 +22,7 @@ package org.eclipse.aether.resolution;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.RepositorySystem;
 import org.eclipse.aether.RepositorySystemSession;
@@ -45,22 +46,18 @@ public final class VersionResult
 
     /**
      * Creates a new result for the specified request.
-     * 
+     *
      * @param request The resolution request, must not be {@code null}.
      */
     public VersionResult( VersionRequest request )
     {
-        if ( request == null )
-        {
-            throw new IllegalArgumentException( "version request has not been specified" );
-        }
-        this.request = request;
+        this.request = requireNonNull( request, "version request cannot be null" );
         exceptions = Collections.emptyList();
     }
 
     /**
      * Gets the resolution request that was made.
-     * 
+     *
      * @return The resolution request, never {@code null}.
      */
     public VersionRequest getRequest()

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/transfer/TransferEvent.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/transfer/TransferEvent.java b/maven-resolver-api/src/main/java/org/eclipse/aether/transfer/TransferEvent.java
index 1599a82..901f317 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/transfer/TransferEvent.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/transfer/TransferEvent.java
@@ -20,12 +20,13 @@ package org.eclipse.aether.transfer;
  */
 
 import java.nio.ByteBuffer;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.RepositorySystemSession;
 
 /**
  * An event fired to a transfer listener during an artifact/metadata transfer.
- * 
+ *
  * @see TransferListener
  * @see TransferEvent.Builder
  */
@@ -237,22 +238,14 @@ public final class TransferEvent
 
         /**
          * Creates a new transfer event builder for the specified session and the given resource.
-         * 
+         *
          * @param session The repository system session, must not be {@code null}.
          * @param resource The resource being transferred, must not be {@code null}.
          */
         public Builder( RepositorySystemSession session, TransferResource resource )
         {
-            if ( session == null )
-            {
-                throw new IllegalArgumentException( "session not specified" );
-            }
-            if ( resource == null )
-            {
-                throw new IllegalArgumentException( "transfer resource not specified" );
-            }
-            this.session = session;
-            this.resource = resource;
+            this.session = requireNonNull( session, "repository system session cannot be null" );
+            this.resource = requireNonNull( resource, "transfer resource cannot be null" );
             type = EventType.INITIATED;
             requestType = RequestType.GET;
         }
@@ -283,17 +276,13 @@ public final class TransferEvent
          * Sets the type of the event and resets event-specific fields. In more detail, the data buffer and the
          * exception fields are set to {@code null}. Furthermore, the total number of transferred bytes is set to
          * {@code 0} if the event type is {@link EventType#STARTED}.
-         * 
+         *
          * @param type The type of the event, must not be {@code null}.
          * @return This event builder for chaining, never {@code null}.
          */
         public Builder resetType( EventType type )
         {
-            if ( type == null )
-            {
-                throw new IllegalArgumentException( "event type not specified" );
-            }
-            this.type = type;
+            this.type = requireNonNull( type, "event type cannot be null" );
             dataBuffer = null;
             exception = null;
             switch ( type )
@@ -309,33 +298,25 @@ public final class TransferEvent
         /**
          * Sets the type of the event. When re-using the same builder to generate a sequence of events for one transfer,
          * {@link #resetType(TransferEvent.EventType)} might be more handy.
-         * 
+         *
          * @param type The type of the event, must not be {@code null}.
          * @return This event builder for chaining, never {@code null}.
          */
         public Builder setType( EventType type )
         {
-            if ( type == null )
-            {
-                throw new IllegalArgumentException( "event type not specified" );
-            }
-            this.type = type;
+            this.type = requireNonNull( type, "event type cannot be null" );
             return this;
         }
 
         /**
          * Sets the type of the request/transfer.
-         * 
+         *
          * @param requestType The request/transfer type, must not be {@code null}.
          * @return This event builder for chaining, never {@code null}.
          */
         public Builder setRequestType( RequestType requestType )
         {
-            if ( requestType == null )
-            {
-                throw new IllegalArgumentException( "request type not specified" );
-            }
-            this.requestType = requestType;
+            this.requestType = requireNonNull( requestType, "request type cannot be null" );
             return this;
         }
 

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/main/java/org/eclipse/aether/version/VersionRange.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/version/VersionRange.java b/maven-resolver-api/src/main/java/org/eclipse/aether/version/VersionRange.java
index e355cf5..fbbb808 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/version/VersionRange.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/version/VersionRange.java
@@ -19,6 +19,8 @@ package org.eclipse.aether.version;
  * under the License.
  */
 
+import static java.util.Objects.requireNonNull;
+
 /**
  * A range of versions.
  */
@@ -61,23 +63,19 @@ public interface VersionRange
 
         /**
          * Creates a new bound with the specified properties.
-         * 
+         *
          * @param version The bounding version, must not be {@code null}.
          * @param inclusive A flag whether the specified version is included in the range or not.
          */
         public Bound( Version version, boolean inclusive )
         {
-            if ( version == null )
-            {
-                throw new IllegalArgumentException( "version missing" );
-            }
-            this.version = version;
+            this.version = requireNonNull( version, "version cannot be null" );
             this.inclusive = inclusive;
         }
 
         /**
          * Gets the bounding version.
-         * 
+         *
          * @return The bounding version, never {@code null}.
          */
         public Version getVersion()

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-api/src/test/java/org/eclipse/aether/repository/RemoteRepositoryBuilderTest.java
----------------------------------------------------------------------
diff --git a/maven-resolver-api/src/test/java/org/eclipse/aether/repository/RemoteRepositoryBuilderTest.java b/maven-resolver-api/src/test/java/org/eclipse/aether/repository/RemoteRepositoryBuilderTest.java
index a384705..e2c15e3 100644
--- a/maven-resolver-api/src/test/java/org/eclipse/aether/repository/RemoteRepositoryBuilderTest.java
+++ b/maven-resolver-api/src/test/java/org/eclipse/aether/repository/RemoteRepositoryBuilderTest.java
@@ -48,7 +48,7 @@ public class RemoteRepositoryBuilderTest
         assertSame( prototype, builder.build() );
     }
 
-    @Test( expected = IllegalArgumentException.class )
+    @Test( expected = NullPointerException.class )
     public void testPrototypeMandatory()
     {
         new Builder( null );

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-connector-basic/src/main/java/org/eclipse/aether/connector/basic/BasicRepositoryConnector.java
----------------------------------------------------------------------
diff --git a/maven-resolver-connector-basic/src/main/java/org/eclipse/aether/connector/basic/BasicRepositoryConnector.java b/maven-resolver-connector-basic/src/main/java/org/eclipse/aether/connector/basic/BasicRepositoryConnector.java
index 4d8a8cf..d96b5ad 100644
--- a/maven-resolver-connector-basic/src/main/java/org/eclipse/aether/connector/basic/BasicRepositoryConnector.java
+++ b/maven-resolver-connector-basic/src/main/java/org/eclipse/aether/connector/basic/BasicRepositoryConnector.java
@@ -27,6 +27,7 @@ import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import static java.util.Objects.requireNonNull;
 import java.util.Set;
 import java.util.concurrent.Executor;
 import java.util.concurrent.ExecutorService;
@@ -400,7 +401,7 @@ final class BasicRepositoryConnector
                               List<RepositoryLayout.Checksum> checksums, TransferTransportListener<?> listener )
         {
             super( path, listener );
-            this.file = file;
+            this.file = requireNonNull( file, "destination file cannot be null" );
             checksumValidator =
                 new ChecksumValidator( logger, file, fileProcessor, this, checksumPolicy, safe( checksums ) );
         }
@@ -432,10 +433,6 @@ final class BasicRepositoryConnector
         protected void runTask()
             throws Exception
         {
-            if ( file == null )
-            {
-                throw new IllegalArgumentException( "destination file has not been specified" );
-            }
             fileProcessor.mkdirs( file.getParentFile() );
 
             PartialFile partFile = partialFileFactory.newInstance( file, this );
@@ -505,17 +502,13 @@ final class BasicRepositoryConnector
                               TransferTransportListener<?> listener )
         {
             super( path, listener );
-            this.file = file;
+            this.file = requireNonNull( file, "source file cannot be null" );
             this.checksums = safe( checksums );
         }
 
         protected void runTask()
             throws Exception
         {
-            if ( file == null )
-            {
-                throw new IllegalArgumentException( "source file has not been specified" );
-            }
             transporter.put( new PutTask( path ).setDataFile( file ).setListener( listener ) );
             uploadChecksums( file, path );
         }

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-connector-basic/src/main/java/org/eclipse/aether/connector/basic/BasicRepositoryConnectorFactory.java
----------------------------------------------------------------------
diff --git a/maven-resolver-connector-basic/src/main/java/org/eclipse/aether/connector/basic/BasicRepositoryConnectorFactory.java b/maven-resolver-connector-basic/src/main/java/org/eclipse/aether/connector/basic/BasicRepositoryConnectorFactory.java
index 8338daf..c218744 100644
--- a/maven-resolver-connector-basic/src/main/java/org/eclipse/aether/connector/basic/BasicRepositoryConnectorFactory.java
+++ b/maven-resolver-connector-basic/src/main/java/org/eclipse/aether/connector/basic/BasicRepositoryConnectorFactory.java
@@ -22,6 +22,8 @@ package org.eclipse.aether.connector.basic;
 import javax.inject.Inject;
 import javax.inject.Named;
 
+import static java.util.Objects.requireNonNull;
+
 import org.eclipse.aether.RepositorySystemSession;
 import org.eclipse.aether.repository.RemoteRepository;
 import org.eclipse.aether.spi.connector.RepositoryConnector;
@@ -104,65 +106,49 @@ public final class BasicRepositoryConnectorFactory
 
     /**
      * Sets the transporter provider to use for this component.
-     * 
+     *
      * @param transporterProvider The transporter provider to use, must not be {@code null}.
      * @return This component for chaining, never {@code null}.
      */
     public BasicRepositoryConnectorFactory setTransporterProvider( TransporterProvider transporterProvider )
     {
-        if ( transporterProvider == null )
-        {
-            throw new IllegalArgumentException( "transporter provider has not been specified" );
-        }
-        this.transporterProvider = transporterProvider;
+        this.transporterProvider = requireNonNull( transporterProvider, "transporter provider cannot be null" );
         return this;
     }
 
     /**
      * Sets the repository layout provider to use for this component.
-     * 
+     *
      * @param layoutProvider The repository layout provider to use, must not be {@code null}.
      * @return This component for chaining, never {@code null}.
      */
     public BasicRepositoryConnectorFactory setRepositoryLayoutProvider( RepositoryLayoutProvider layoutProvider )
     {
-        if ( layoutProvider == null )
-        {
-            throw new IllegalArgumentException( "repository layout provider has not been specified" );
-        }
-        this.layoutProvider = layoutProvider;
+        this.layoutProvider =  requireNonNull( layoutProvider, "repository layout provider cannot be null" );
         return this;
     }
 
     /**
      * Sets the checksum policy provider to use for this component.
-     * 
+     *
      * @param checksumPolicyProvider The checksum policy provider to use, must not be {@code null}.
      * @return This component for chaining, never {@code null}.
      */
     public BasicRepositoryConnectorFactory setChecksumPolicyProvider( ChecksumPolicyProvider checksumPolicyProvider )
     {
-        if ( checksumPolicyProvider == null )
-        {
-            throw new IllegalArgumentException( "checksum policy provider has not been specified" );
-        }
-        this.checksumPolicyProvider = checksumPolicyProvider;
+        this.checksumPolicyProvider = requireNonNull( checksumPolicyProvider, "checksum policy provider cannot be null" );
         return this;
     }
 
     /**
      * Sets the file processor to use for this component.
-     * 
+     *
      * @param fileProcessor The file processor to use, must not be {@code null}.
      * @return This component for chaining, never {@code null}.
      */
     public BasicRepositoryConnectorFactory setFileProcessor( FileProcessor fileProcessor )
     {
-        if ( fileProcessor == null )
-        {
-            throw new IllegalArgumentException( "file processor has not been specified" );
-        }
-        this.fileProcessor = fileProcessor;
+        this.fileProcessor = requireNonNull( fileProcessor, "file processor cannot be null" );
         return this;
     }
 

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-impl/src/main/java/org/eclipse/aether/impl/DefaultServiceLocator.java
----------------------------------------------------------------------
diff --git a/maven-resolver-impl/src/main/java/org/eclipse/aether/impl/DefaultServiceLocator.java b/maven-resolver-impl/src/main/java/org/eclipse/aether/impl/DefaultServiceLocator.java
index 4d71b88..52ae3c2 100644
--- a/maven-resolver-impl/src/main/java/org/eclipse/aether/impl/DefaultServiceLocator.java
+++ b/maven-resolver-impl/src/main/java/org/eclipse/aether/impl/DefaultServiceLocator.java
@@ -28,6 +28,7 @@ import java.util.HashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.RepositorySystem;
 import org.eclipse.aether.internal.impl.DefaultArtifactResolver;
@@ -90,11 +91,7 @@ public final class DefaultServiceLocator
 
         public Entry( Class<T> type )
         {
-            if ( type == null )
-            {
-                throw new IllegalArgumentException( "service type not specified" );
-            }
-            this.type = type;
+            this.type = requireNonNull( type, "service type cannot be null" );
             providers = new LinkedHashSet<Object>( 8 );
         }
 
@@ -105,11 +102,7 @@ public final class DefaultServiceLocator
             {
                 for ( T service : services )
                 {
-                    if ( service == null )
-                    {
-                        throw new IllegalArgumentException( "service instance not specified" );
-                    }
-                    providers.add( service );
+                    providers.add( requireNonNull( service, "service instance cannot be null" ) );
                 }
             }
             instances = null;
@@ -123,11 +116,7 @@ public final class DefaultServiceLocator
 
         public synchronized void addService( Class<? extends T> impl )
         {
-            if ( impl == null )
-            {
-                throw new IllegalArgumentException( "implementation class not specified" );
-            }
-            providers.add( impl );
+            providers.add( requireNonNull( impl, "implementation class cannot be null" ) );
             instances = null;
         }
 
@@ -234,12 +223,8 @@ public final class DefaultServiceLocator
 
     private <T> Entry<T> getEntry( Class<T> type, boolean create )
     {
-        if ( type == null )
-        {
-            throw new IllegalArgumentException( "service type not specified" );
-        }
         @SuppressWarnings( "unchecked" )
-        Entry<T> entry = (Entry<T>) entries.get( type );
+        Entry<T> entry = (Entry<T>) entries.get( requireNonNull( type, "service type cannot be null" ) );
         if ( entry == null && create )
         {
             entry = new Entry<T>( type );

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultArtifactResolver.java
----------------------------------------------------------------------
diff --git a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultArtifactResolver.java b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultArtifactResolver.java
index 37d296e..9ccffc8 100644
--- a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultArtifactResolver.java
+++ b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultArtifactResolver.java
@@ -26,6 +26,7 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
+import static java.util.Objects.requireNonNull;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import javax.inject.Inject;
@@ -148,81 +149,49 @@ public class DefaultArtifactResolver
 
     public DefaultArtifactResolver setFileProcessor( FileProcessor fileProcessor )
     {
-        if ( fileProcessor == null )
-        {
-            throw new IllegalArgumentException( "file processor has not been specified" );
-        }
-        this.fileProcessor = fileProcessor;
+        this.fileProcessor = requireNonNull( fileProcessor, "file processor cannot be null" );
         return this;
     }
 
     public DefaultArtifactResolver setRepositoryEventDispatcher( RepositoryEventDispatcher repositoryEventDispatcher )
     {
-        if ( repositoryEventDispatcher == null )
-        {
-            throw new IllegalArgumentException( "repository event dispatcher has not been specified" );
-        }
-        this.repositoryEventDispatcher = repositoryEventDispatcher;
+        this.repositoryEventDispatcher = requireNonNull( repositoryEventDispatcher, "repository event dispatcher cannot be null" );
         return this;
     }
 
     public DefaultArtifactResolver setVersionResolver( VersionResolver versionResolver )
     {
-        if ( versionResolver == null )
-        {
-            throw new IllegalArgumentException( "version resolver has not been specified" );
-        }
-        this.versionResolver = versionResolver;
+        this.versionResolver = requireNonNull( versionResolver, "version resolver cannot be null" );
         return this;
     }
 
     public DefaultArtifactResolver setUpdateCheckManager( UpdateCheckManager updateCheckManager )
     {
-        if ( updateCheckManager == null )
-        {
-            throw new IllegalArgumentException( "update check manager has not been specified" );
-        }
-        this.updateCheckManager = updateCheckManager;
+        this.updateCheckManager = requireNonNull( updateCheckManager, "update check manager cannot be null" );
         return this;
     }
 
     public DefaultArtifactResolver setRepositoryConnectorProvider( RepositoryConnectorProvider repositoryConnectorProvider )
     {
-        if ( repositoryConnectorProvider == null )
-        {
-            throw new IllegalArgumentException( "repository connector provider has not been specified" );
-        }
-        this.repositoryConnectorProvider = repositoryConnectorProvider;
+        this.repositoryConnectorProvider = requireNonNull( repositoryConnectorProvider, "repository connector provider cannot be null" );
         return this;
     }
 
     public DefaultArtifactResolver setRemoteRepositoryManager( RemoteRepositoryManager remoteRepositoryManager )
     {
-        if ( remoteRepositoryManager == null )
-        {
-            throw new IllegalArgumentException( "remote repository manager has not been specified" );
-        }
-        this.remoteRepositoryManager = remoteRepositoryManager;
+        this.remoteRepositoryManager = requireNonNull( remoteRepositoryManager, "remote repository provider cannot be null" );
         return this;
     }
 
     public DefaultArtifactResolver setSyncContextFactory( SyncContextFactory syncContextFactory )
     {
-        if ( syncContextFactory == null )
-        {
-            throw new IllegalArgumentException( "sync context factory has not been specified" );
-        }
-        this.syncContextFactory = syncContextFactory;
+        this.syncContextFactory = requireNonNull( syncContextFactory, "sync context factory cannot be null" );
         return this;
     }
 
     public DefaultArtifactResolver setOfflineController( OfflineController offlineController )
     {
-        if ( offlineController == null )
-        {
-            throw new IllegalArgumentException( "offline controller has not been specified" );
-        }
-        this.offlineController = offlineController;
+        this.offlineController = requireNonNull( offlineController, "offline controller cannot be null" );
         return this;
     }
 

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultDependencyCollector.java
----------------------------------------------------------------------
diff --git a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultDependencyCollector.java b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultDependencyCollector.java
index 528200c..353f0c4 100644
--- a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultDependencyCollector.java
+++ b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultDependencyCollector.java
@@ -27,6 +27,7 @@ import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import static java.util.Objects.requireNonNull;
 
 import javax.inject.Inject;
 import javax.inject.Named;
@@ -123,31 +124,19 @@ public class DefaultDependencyCollector
 
     public DefaultDependencyCollector setRemoteRepositoryManager( RemoteRepositoryManager remoteRepositoryManager )
     {
-        if ( remoteRepositoryManager == null )
-        {
-            throw new IllegalArgumentException( "remote repository manager has not been specified" );
-        }
-        this.remoteRepositoryManager = remoteRepositoryManager;
+        this.remoteRepositoryManager = requireNonNull( remoteRepositoryManager, "remote repository provider cannot be null" );
         return this;
     }
 
     public DefaultDependencyCollector setArtifactDescriptorReader( ArtifactDescriptorReader artifactDescriptorReader )
     {
-        if ( artifactDescriptorReader == null )
-        {
-            throw new IllegalArgumentException( "artifact descriptor reader has not been specified" );
-        }
-        descriptorReader = artifactDescriptorReader;
+        descriptorReader = requireNonNull( artifactDescriptorReader, "artifact descriptor reader cannot be null" );
         return this;
     }
 
     public DefaultDependencyCollector setVersionRangeResolver( VersionRangeResolver versionRangeResolver )
     {
-        if ( versionRangeResolver == null )
-        {
-            throw new IllegalArgumentException( "version range resolver has not been specified" );
-        }
-        this.versionRangeResolver = versionRangeResolver;
+        this.versionRangeResolver = requireNonNull( versionRangeResolver, "version range resolver cannot be null" );
         return this;
     }
 

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultDependencyGraphTransformationContext.java
----------------------------------------------------------------------
diff --git a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultDependencyGraphTransformationContext.java b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultDependencyGraphTransformationContext.java
index d877ad6..9eb3e2f 100644
--- a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultDependencyGraphTransformationContext.java
+++ b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultDependencyGraphTransformationContext.java
@@ -21,6 +21,7 @@ package org.eclipse.aether.internal.impl;
 
 import java.util.HashMap;
 import java.util.Map;
+import static java.util.Objects.requireNonNull;
 
 import org.eclipse.aether.RepositorySystemSession;
 import org.eclipse.aether.collection.DependencyGraphTransformationContext;
@@ -48,19 +49,12 @@ class DefaultDependencyGraphTransformationContext
 
     public Object get( Object key )
     {
-        if ( key == null )
-        {
-            throw new IllegalArgumentException( "key must not be null" );
-        }
-        return map.get( key );
+        return map.get( requireNonNull( key, "key cannot be null" ) );
     }
 
     public Object put( Object key, Object value )
     {
-        if ( key == null )
-        {
-            throw new IllegalArgumentException( "key must not be null" );
-        }
+        requireNonNull( key, "key cannot be null" );
         if ( value != null )
         {
             return map.put( key, value );

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultDeployer.java
----------------------------------------------------------------------
diff --git a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultDeployer.java b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultDeployer.java
index 56951fa..48240b2 100644
--- a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultDeployer.java
+++ b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultDeployer.java
@@ -26,6 +26,7 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.IdentityHashMap;
 import java.util.List;
+import static java.util.Objects.requireNonNull;
 import java.util.Set;
 
 import javax.inject.Inject;
@@ -143,61 +144,37 @@ public class DefaultDeployer
 
     public DefaultDeployer setFileProcessor( FileProcessor fileProcessor )
     {
-        if ( fileProcessor == null )
-        {
-            throw new IllegalArgumentException( "file processor has not been specified" );
-        }
-        this.fileProcessor = fileProcessor;
+        this.fileProcessor = requireNonNull( fileProcessor, "file processor cannot be null" );
         return this;
     }
 
     public DefaultDeployer setRepositoryEventDispatcher( RepositoryEventDispatcher repositoryEventDispatcher )
     {
-        if ( repositoryEventDispatcher == null )
-        {
-            throw new IllegalArgumentException( "repository event dispatcher has not been specified" );
-        }
-        this.repositoryEventDispatcher = repositoryEventDispatcher;
+        this.repositoryEventDispatcher = requireNonNull( repositoryEventDispatcher, "repository event dispatcher cannot be null" );
         return this;
     }
 
     public DefaultDeployer setRepositoryConnectorProvider( RepositoryConnectorProvider repositoryConnectorProvider )
     {
-        if ( repositoryConnectorProvider == null )
-        {
-            throw new IllegalArgumentException( "repository connector provider has not been specified" );
-        }
-        this.repositoryConnectorProvider = repositoryConnectorProvider;
+        this.repositoryConnectorProvider = requireNonNull( repositoryConnectorProvider, "repository connector provider cannot be null" );
         return this;
     }
 
     public DefaultDeployer setRemoteRepositoryManager( RemoteRepositoryManager remoteRepositoryManager )
     {
-        if ( remoteRepositoryManager == null )
-        {
-            throw new IllegalArgumentException( "remote repository manager has not been specified" );
-        }
-        this.remoteRepositoryManager = remoteRepositoryManager;
+        this.remoteRepositoryManager = requireNonNull( remoteRepositoryManager, "remote repository provider cannot be null" );
         return this;
     }
 
     public DefaultDeployer setUpdateCheckManager( UpdateCheckManager updateCheckManager )
     {
-        if ( updateCheckManager == null )
-        {
-            throw new IllegalArgumentException( "update check manager has not been specified" );
-        }
-        this.updateCheckManager = updateCheckManager;
+        this.updateCheckManager = requireNonNull( updateCheckManager, "update check manager cannot be null" );
         return this;
     }
 
     public DefaultDeployer addMetadataGeneratorFactory( MetadataGeneratorFactory factory )
     {
-        if ( factory == null )
-        {
-            throw new IllegalArgumentException( "metadata generator factory has not been specified" );
-        }
-        metadataFactories.add( factory );
+        metadataFactories.add( requireNonNull( factory, "metadata generator factory cannot be null" ) );
         return this;
     }
 
@@ -216,21 +193,13 @@ public class DefaultDeployer
 
     public DefaultDeployer setSyncContextFactory( SyncContextFactory syncContextFactory )
     {
-        if ( syncContextFactory == null )
-        {
-            throw new IllegalArgumentException( "sync context factory has not been specified" );
-        }
-        this.syncContextFactory = syncContextFactory;
+        this.syncContextFactory = requireNonNull( syncContextFactory, "sync context factory cannot be null" );
         return this;
     }
 
     public DefaultDeployer setOfflineController( OfflineController offlineController )
     {
-        if ( offlineController == null )
-        {
-            throw new IllegalArgumentException( "offline controller has not been specified" );
-        }
-        this.offlineController = offlineController;
+        this.offlineController = requireNonNull( offlineController, "offline controller cannot be null" );
         return this;
     }
 

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultInstaller.java
----------------------------------------------------------------------
diff --git a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultInstaller.java b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultInstaller.java
index ea95371..008f4b3 100644
--- a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultInstaller.java
+++ b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultInstaller.java
@@ -24,6 +24,7 @@ import java.util.ArrayList;
 import java.util.Collection;
 import java.util.IdentityHashMap;
 import java.util.List;
+import static java.util.Objects.requireNonNull;
 import java.util.Set;
 
 import javax.inject.Inject;
@@ -106,31 +107,19 @@ public class DefaultInstaller
 
     public DefaultInstaller setFileProcessor( FileProcessor fileProcessor )
     {
-        if ( fileProcessor == null )
-        {
-            throw new IllegalArgumentException( "file processor has not been specified" );
-        }
-        this.fileProcessor = fileProcessor;
+        this.fileProcessor = requireNonNull( fileProcessor, "file processor cannot be null" );
         return this;
     }
 
     public DefaultInstaller setRepositoryEventDispatcher( RepositoryEventDispatcher repositoryEventDispatcher )
     {
-        if ( repositoryEventDispatcher == null )
-        {
-            throw new IllegalArgumentException( "repository event dispatcher has not been specified" );
-        }
-        this.repositoryEventDispatcher = repositoryEventDispatcher;
+        this.repositoryEventDispatcher = requireNonNull( repositoryEventDispatcher, "repository event dispatcher cannot be null" );
         return this;
     }
 
     public DefaultInstaller addMetadataGeneratorFactory( MetadataGeneratorFactory factory )
     {
-        if ( factory == null )
-        {
-            throw new IllegalArgumentException( "metadata generator factory has not been specified" );
-        }
-        metadataFactories.add( factory );
+        metadataFactories.add( requireNonNull( factory, "metadata generator factory cannot be null" ) );
         return this;
     }
 
@@ -149,11 +138,7 @@ public class DefaultInstaller
 
     public DefaultInstaller setSyncContextFactory( SyncContextFactory syncContextFactory )
     {
-        if ( syncContextFactory == null )
-        {
-            throw new IllegalArgumentException( "sync context factory has not been specified" );
-        }
-        this.syncContextFactory = syncContextFactory;
+        this.syncContextFactory = requireNonNull( syncContextFactory, "sync context factory cannot be null" );
         return this;
     }
 

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultLocalRepositoryProvider.java
----------------------------------------------------------------------
diff --git a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultLocalRepositoryProvider.java b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultLocalRepositoryProvider.java
index 1f0597a..ea89804 100644
--- a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultLocalRepositoryProvider.java
+++ b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultLocalRepositoryProvider.java
@@ -22,6 +22,7 @@ package org.eclipse.aether.internal.impl;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import static java.util.Objects.requireNonNull;
 import java.util.Set;
 
 import javax.inject.Inject;
@@ -76,11 +77,7 @@ public class DefaultLocalRepositoryProvider
 
     public DefaultLocalRepositoryProvider addLocalRepositoryManagerFactory( LocalRepositoryManagerFactory factory )
     {
-        if ( factory == null )
-        {
-            throw new IllegalArgumentException( "Local repository manager factory has not been specified." );
-        }
-        managerFactories.add( factory );
+        managerFactories.add( requireNonNull( factory, "local repository manager factory cannot be null" ) );
         return this;
     }
 

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultMetadataResolver.java
----------------------------------------------------------------------
diff --git a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultMetadataResolver.java b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultMetadataResolver.java
index c751112..f820ec9 100644
--- a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultMetadataResolver.java
+++ b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultMetadataResolver.java
@@ -27,6 +27,7 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import static java.util.Objects.requireNonNull;
 import java.util.concurrent.Executor;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.LinkedBlockingQueue;
@@ -138,61 +139,37 @@ public class DefaultMetadataResolver
 
     public DefaultMetadataResolver setRepositoryEventDispatcher( RepositoryEventDispatcher repositoryEventDispatcher )
     {
-        if ( repositoryEventDispatcher == null )
-        {
-            throw new IllegalArgumentException( "repository event dispatcher has not been specified" );
-        }
-        this.repositoryEventDispatcher = repositoryEventDispatcher;
+        this.repositoryEventDispatcher = requireNonNull( repositoryEventDispatcher, "repository event dispatcher cannot be null" );
         return this;
     }
 
     public DefaultMetadataResolver setUpdateCheckManager( UpdateCheckManager updateCheckManager )
     {
-        if ( updateCheckManager == null )
-        {
-            throw new IllegalArgumentException( "update check manager has not been specified" );
-        }
-        this.updateCheckManager = updateCheckManager;
+        this.updateCheckManager = requireNonNull( updateCheckManager, "update check manager cannot be null" );
         return this;
     }
 
     public DefaultMetadataResolver setRepositoryConnectorProvider( RepositoryConnectorProvider repositoryConnectorProvider )
     {
-        if ( repositoryConnectorProvider == null )
-        {
-            throw new IllegalArgumentException( "repository connector provider has not been specified" );
-        }
-        this.repositoryConnectorProvider = repositoryConnectorProvider;
+        this.repositoryConnectorProvider = requireNonNull( repositoryConnectorProvider, "repository connector provider cannot be null" );
         return this;
     }
 
     public DefaultMetadataResolver setRemoteRepositoryManager( RemoteRepositoryManager remoteRepositoryManager )
     {
-        if ( remoteRepositoryManager == null )
-        {
-            throw new IllegalArgumentException( "remote repository manager has not been specified" );
-        }
-        this.remoteRepositoryManager = remoteRepositoryManager;
+        this.remoteRepositoryManager = requireNonNull( remoteRepositoryManager, "remote repository provider cannot be null" );
         return this;
     }
 
     public DefaultMetadataResolver setSyncContextFactory( SyncContextFactory syncContextFactory )
     {
-        if ( syncContextFactory == null )
-        {
-            throw new IllegalArgumentException( "sync context factory has not been specified" );
-        }
-        this.syncContextFactory = syncContextFactory;
+        this.syncContextFactory = requireNonNull( syncContextFactory, "sync context factory cannot be null" );
         return this;
     }
 
     public DefaultMetadataResolver setOfflineController( OfflineController offlineController )
     {
-        if ( offlineController == null )
-        {
-            throw new IllegalArgumentException( "offline controller has not been specified" );
-        }
-        this.offlineController = offlineController;
+        this.offlineController = requireNonNull( offlineController, "offline controller cannot be null" );
         return this;
     }
 

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRemoteRepositoryManager.java
----------------------------------------------------------------------
diff --git a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRemoteRepositoryManager.java b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRemoteRepositoryManager.java
index 148bf4d..a1110b4 100644
--- a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRemoteRepositoryManager.java
+++ b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRemoteRepositoryManager.java
@@ -23,6 +23,7 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.ListIterator;
+import static java.util.Objects.requireNonNull;
 
 import javax.inject.Inject;
 import javax.inject.Named;
@@ -121,21 +122,13 @@ public class DefaultRemoteRepositoryManager
 
     public DefaultRemoteRepositoryManager setUpdatePolicyAnalyzer( UpdatePolicyAnalyzer updatePolicyAnalyzer )
     {
-        if ( updatePolicyAnalyzer == null )
-        {
-            throw new IllegalArgumentException( "update policy analyzer has not been specified" );
-        }
-        this.updatePolicyAnalyzer = updatePolicyAnalyzer;
+        this.updatePolicyAnalyzer = requireNonNull( updatePolicyAnalyzer, "update policy analyzer cannot be null" );
         return this;
     }
 
     public DefaultRemoteRepositoryManager setChecksumPolicyProvider( ChecksumPolicyProvider checksumPolicyProvider )
     {
-        if ( checksumPolicyProvider == null )
-        {
-            throw new IllegalArgumentException( "checksum policy provider has not been specified" );
-        }
-        this.checksumPolicyProvider = checksumPolicyProvider;
+        this.checksumPolicyProvider = requireNonNull( checksumPolicyProvider, "checksum policy provider cannot be null" );
         return this;
     }
 

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRepositoryConnectorProvider.java
----------------------------------------------------------------------
diff --git a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRepositoryConnectorProvider.java b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRepositoryConnectorProvider.java
index 10fdc23..68f3301 100644
--- a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRepositoryConnectorProvider.java
+++ b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRepositoryConnectorProvider.java
@@ -22,6 +22,7 @@ package org.eclipse.aether.internal.impl;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import static java.util.Objects.requireNonNull;
 import java.util.Set;
 
 import javax.inject.Inject;
@@ -78,11 +79,7 @@ public class DefaultRepositoryConnectorProvider
 
     public DefaultRepositoryConnectorProvider addRepositoryConnectorFactory( RepositoryConnectorFactory factory )
     {
-        if ( factory == null )
-        {
-            throw new IllegalArgumentException( "repository connector factory has not been specified" );
-        }
-        connectorFactories.add( factory );
+        connectorFactories.add( requireNonNull( factory, "repository connector factory cannot be null" ) );
         return this;
     }
 
@@ -102,10 +99,7 @@ public class DefaultRepositoryConnectorProvider
     public RepositoryConnector newRepositoryConnector( RepositorySystemSession session, RemoteRepository repository )
         throws NoRepositoryConnectorException
     {
-        if ( repository == null )
-        {
-            throw new IllegalArgumentException( "remote repository has not been specified" );
-        }
+        requireNonNull( repository, "remote repository cannot be null" );
 
         PrioritizedComponents<RepositoryConnectorFactory> factories =
             new PrioritizedComponents<RepositoryConnectorFactory>( session );

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRepositoryEventDispatcher.java
----------------------------------------------------------------------
diff --git a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRepositoryEventDispatcher.java b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRepositoryEventDispatcher.java
index 2e56c93..9970e62 100644
--- a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRepositoryEventDispatcher.java
+++ b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRepositoryEventDispatcher.java
@@ -21,6 +21,7 @@ package org.eclipse.aether.internal.impl;
 
 import java.util.ArrayList;
 import java.util.Collection;
+import static java.util.Objects.requireNonNull;
 import java.util.Set;
 
 import javax.inject.Inject;
@@ -66,11 +67,7 @@ public class DefaultRepositoryEventDispatcher
 
     public DefaultRepositoryEventDispatcher addRepositoryListener( RepositoryListener listener )
     {
-        if ( listener == null )
-        {
-            throw new IllegalArgumentException( "repository listener has not been specified" );
-        }
-        this.listeners.add( listener );
+        this.listeners.add( requireNonNull( listener, "repository listener cannot be null" ) );
         return this;
     }
 

http://git-wip-us.apache.org/repos/asf/maven-resolver/blob/362ce50e/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRepositoryLayoutProvider.java
----------------------------------------------------------------------
diff --git a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRepositoryLayoutProvider.java b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRepositoryLayoutProvider.java
index 9cc6371..6f424e8 100644
--- a/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRepositoryLayoutProvider.java
+++ b/maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultRepositoryLayoutProvider.java
@@ -22,6 +22,7 @@ package org.eclipse.aether.internal.impl;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import static java.util.Objects.requireNonNull;
 import java.util.Set;
 
 import javax.inject.Inject;
@@ -76,11 +77,7 @@ public final class DefaultRepositoryLayoutProvider
 
     public DefaultRepositoryLayoutProvider addRepositoryLayoutFactory( RepositoryLayoutFactory factory )
     {
-        if ( factory == null )
-        {
-            throw new IllegalArgumentException( "layout factory has not been specified" );
-        }
-        factories.add( factory );
+        factories.add( requireNonNull( factory, "layout factory cannot be null" ) );
         return this;
     }
 
@@ -100,10 +97,7 @@ public final class DefaultRepositoryLayoutProvider
     public RepositoryLayout newRepositoryLayout( RepositorySystemSession session, RemoteRepository repository )
         throws NoRepositoryLayoutException
     {
-        if ( repository == null )
-        {
-            throw new IllegalArgumentException( "remote repository has not been specified" );
-        }
+        requireNonNull( repository, "remote repository cannot be null" );
 
         PrioritizedComponents<RepositoryLayoutFactory> factories =
             new PrioritizedComponents<RepositoryLayoutFactory>( session );