code: @SuppressWarnings( "unchecked" )
      public static String createClassPath( MavenProject project, List<Artifact> pluginArtifacts, List<String> outDirs )
      {
          String cp = new String();
          Set<Artifact> classPathElements = Collections.synchronizedSet( new LinkedHashSet<Artifact>() );
          Set<Artifact> dependencyArtifacts = project.getDependencyArtifacts();
          classPathElements.addAll( dependencyArtifacts == null ? Collections.<Artifact>emptySet() : dependencyArtifacts );
          classPathElements.addAll( project.getArtifacts() );
          classPathElements.addAll( pluginArtifacts == null ? Collections.<Artifact>emptySet() : pluginArtifacts );
          for ( Artifact classPathElement  : classPathElements )
          {
              File artifact = classPathElement.getFile();
              if ( null != artifact )
              {
                String type = classPathElement.getType();
                if (!type.equals("pom")){
                  cp += classPathElement.getFile().getAbsolutePath();
                  cp += File.pathSeparatorChar;                
                }
              }
          }
          Iterator<String> outIter = outDirs.iterator();
          while ( outIter.hasNext() )
          {
              cp += outIter.next();
              cp += File.pathSeparatorChar;
          }
  
          if ( cp.endsWith( "" + File.pathSeparatorChar ) )
          {
              cp = cp.substring( 0, cp.length() - 1 );
          }
  
          cp = StringUtils.replace( cp, "//", "/" );
          return cp;
      }
docs: Constructs AspectJ compiler classpath string
  
  @param project the Maven Project
  @param pluginArtifacts the plugin Artifacts
  @param outDirs the outputDirectories
  @return a os spesific classpath string