code: public void execute()
          throws MojoExecutionException, MojoFailureException
      {
          File jarFile = new File( outputDirectory, finalName + ".jar" );
          File origJarFile = new File( outputDirectory, finalName + "-b4gwt.jar" );
          if ( origJarFile.exists() )
          {
              if ( !origJarFile.delete() )
              {
                  throw new MojoExecutionException( "Error removing " + origJarFile );
              }
          }
          if ( !jarFile.renameTo( origJarFile ) )
          {
              throw new MojoExecutionException( "Error renaming " + jarFile + " to " + origJarFile );
          }
  
          MavenArchiver archiver = new MavenArchiver();
  
          archiver.setArchiver( jarArchiver );
          archiver.setOutputFile( jarFile );
          archive.setForced( false );
          // It is already created by maven-jar-plugin
          archive.setAddMavenDescriptor( false );
  
          Collection<ResourceFile> files = getAllResourceFiles();
          try
          {
  
              // Avoid annoying messages in log "com/package/Ccc.java already added, skipping"
              List<String> jarExcludes = new Vector<String>();
  
              // Add Sources first since they may already be present in jar from previous run and changed.
              for ( ResourceFile file : files )
              {
                  jarArchiver.addFile( new File( file.basedir, file.fileRelativeName ), file.fileRelativeName );
                  jarExcludes.add( file.fileRelativeName );
              }
  
              // Add the context of original jar excluding resources that we just added base on GWT descriptors
              jarArchiver.addArchivedFileSet( origJarFile, null, jarExcludes.toArray( new String[jarExcludes.size()] ) );
  
              archiver.createArchive( session , getProject(), archive );
          }
          catch ( Exception e )
          {
              throw new MojoExecutionException( "Error assembling JAR", e );
          }
  
      }
docs: {@inheritDoc}
  
  @see org.apache.maven.plugin.Mojo#execute()