diff --git a/maven-compat/src/main/java/org/apache/maven/artifact/ArtifactUtils.java b/maven-compat/src/main/java/org/apache/maven/artifact/ArtifactUtils.java
index be870065ea..ec9a5e5e77 100644
--- a/maven-compat/src/main/java/org/apache/maven/artifact/ArtifactUtils.java
+++ b/maven-compat/src/main/java/org/apache/maven/artifact/ArtifactUtils.java
@@ -146,6 +146,16 @@ public final class ArtifactUtils
         return clone;
     }
 
+    /** Returns <code>to</code> collection */
+    public static <T extends Collection<Artifact>> T copyArtifacts( Collection<Artifact> from, T to )
+    {
+        for ( Artifact artifact : from )
+        {
+            to.add( ArtifactUtils.copyArtifact( artifact ) );
+        }
+        return to;
+    }
+
     private static <T> List<T> copyList( List<T> original )
     {
         List<T> copy = null;
diff --git a/maven-core/src/main/java/org/apache/maven/lifecycle/DefaultLifecycleExecutor.java b/maven-core/src/main/java/org/apache/maven/lifecycle/DefaultLifecycleExecutor.java
index a88f57eef2..9aea3f885c 100644
--- a/maven-core/src/main/java/org/apache/maven/lifecycle/DefaultLifecycleExecutor.java
+++ b/maven-core/src/main/java/org/apache/maven/lifecycle/DefaultLifecycleExecutor.java
@@ -397,12 +397,6 @@ public class DefaultLifecycleExecutor
             MojoDescriptor mojoDescriptor = pluginManager.getMojoDescriptor( 
                 mojoExecution.getGroupId(), mojoExecution.getArtifactId(), mojoExecution.getVersion(), mojoExecution.getGoal(), session.getLocalRepository(), project.getPluginArtifactRepositories() );
 
-            PluginDescriptor pluginDescriptor = mojoDescriptor.getPluginDescriptor();
-            if ( pluginDescriptor.getPlugin().isExtensions() )
-            {
-                pluginDescriptor.setClassRealm( pluginManager.getPluginRealm( session, pluginDescriptor ) );
-            }
-
             requiredDependencyResolutionScope = calculateRequiredDependencyResolutionScope( requiredDependencyResolutionScope, mojoDescriptor.isDependencyResolutionRequired() );          
             
             mojoExecution.setMojoDescriptor( mojoDescriptor );
diff --git a/maven-core/src/main/java/org/apache/maven/project/artifact/DefaultMavenMetadataCache.java b/maven-core/src/main/java/org/apache/maven/project/artifact/DefaultMavenMetadataCache.java
index 5108008d0e..6a73a3fb66 100644
--- a/maven-core/src/main/java/org/apache/maven/project/artifact/DefaultMavenMetadataCache.java
+++ b/maven-core/src/main/java/org/apache/maven/project/artifact/DefaultMavenMetadataCache.java
@@ -18,7 +18,6 @@ package org.apache.maven.project.artifact;
 
 import java.io.File;
 import java.util.ArrayList;
-import java.util.Collection;
 import java.util.HashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
@@ -130,7 +129,7 @@ public class DefaultMavenMetadataCache
         CacheRecord(Artifact pomArtifact, Set<Artifact> artifacts, List<ArtifactRepository> remoteRepositories)
         {
             this.pomArtifact = ArtifactUtils.copyArtifact( pomArtifact );
-            this.artifacts = copyArtifacts( artifacts );
+            this.artifacts = ArtifactUtils.copyArtifacts( artifacts, new ArrayList<Artifact>() );
             this.remoteRepositories = new ArrayList<ArtifactRepository>( remoteRepositories );
 
 
@@ -186,7 +185,7 @@ public class DefaultMavenMetadataCache
         if ( cacheRecord != null && !cacheRecord.isStale() )
         {
             Artifact pomArtifact = ArtifactUtils.copyArtifact( cacheRecord.getArtifact() );
-            Set<Artifact> artifacts = new LinkedHashSet<Artifact>( copyArtifacts( cacheRecord.getArtifacts() ) );
+            Set<Artifact> artifacts = ArtifactUtils.copyArtifacts( cacheRecord.getArtifacts(), new LinkedHashSet<Artifact>() );
             return new ResolutionGroup( pomArtifact, artifacts , cacheRecord.getRemoteRepositories() );
         }
 
@@ -204,16 +203,6 @@ public class DefaultMavenMetadataCache
         cache.put( cacheKey, cacheRecord );
     }
 
-    public static List<Artifact> copyArtifacts( Collection<Artifact> artifacts )
-    {
-        ArrayList<Artifact> result = new ArrayList<Artifact>();
-        for ( Artifact artifact : artifacts )
-        {
-            result.add( ArtifactUtils.copyArtifact( artifact ) );
-        }
-        return result;
-    }
-
     public void flush()
     {
         cache.clear();
diff --git a/maven-core/src/test/java/org/apache/maven/AbstractCoreMavenComponentTestCase.java b/maven-core/src/test/java/org/apache/maven/AbstractCoreMavenComponentTestCase.java
index 112011fad1..7328a4fd15 100644
--- a/maven-core/src/test/java/org/apache/maven/AbstractCoreMavenComponentTestCase.java
+++ b/maven-core/src/test/java/org/apache/maven/AbstractCoreMavenComponentTestCase.java
@@ -154,22 +154,6 @@ public abstract class AbstractCoreMavenComponentTestCase
     {        
         return repositorySystem.createDefaultLocalRepository();        
     }
-
-    protected ArtifactRepository getReactorRepository( MavenProject... projects ) 
-        throws InvalidRepositoryException
-    {
-        Map<String, MavenProject> projectsMap = new LinkedHashMap<String, MavenProject>();
-
-        for ( MavenProject project : projects )
-        {
-            projectsMap.put( ArtifactUtils.key( project.getGroupId(), project.getArtifactId(), project.getVersion() ), project );
-        }
-
-        DelegatingLocalArtifactRepository delegatingLocalArtifactRepository = new DelegatingLocalArtifactRepository( getLocalRepository() );
-        delegatingLocalArtifactRepository.setBuildReactor( new ReactorArtifactRepository( projectsMap ) );
-        
-        return delegatingLocalArtifactRepository;
-    }
     
     protected class ProjectBuilder
     {
diff --git a/pom.xml b/pom.xml
index 74b33436be..a2ca8c46c7 100644
--- a/pom.xml
+++ b/pom.xml
@@ -52,7 +52,7 @@ under the License.
     <easyMockVersion>1.2_Java1.3</easyMockVersion>
     <junitVersion>3.8.2</junitVersion>
     <plexusVersion>1.0-beta-3.0.8-SNAPSHOT</plexusVersion>
-    <plexusInterpolationVersion>1.8.1</plexusInterpolationVersion>
+    <plexusInterpolationVersion>1.9-SNAPSHOT</plexusInterpolationVersion>
     <plexusPluginManagerVersion>1.0-alpha-1</plexusPluginManagerVersion>
     <plexusUtilsVersion>1.5.13-SNAPSHOT</plexusUtilsVersion>
     <plexusJetty6Version>1.6</plexusJetty6Version>