Bug 64298 JAR files already in build path still shown when adding JARs.
When adding JARs to the Java build path in 3.0M9, the JAR's that are already added do not get filtered out anymore like with all previous builds (M8 and lower). Instead, the complete list of all available JARs is shown.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/LibrariesWorkbookPage.java
private CPListElement[] openNewClassFolderDialog(CPListElement existing) {
		String title= (existing == null) ? NewWizardMessages.getString("LibrariesWorkbookPage.NewClassFolderDialog.new.title") : NewWizardMessages.getString("LibrariesWorkbookPage.NewClassFolderDialog.edit.title"); 
		IProject currProject= fCurrJProject.getProject();
		
		NewContainerDialog dialog= new NewContainerDialog(getShell(), title, currProject, getUsedContainers(existing), existing);
		IPath projpath= currProject.getFullPath();
		dialog.setMessage(NewWizardMessages.getFormattedString("LibrariesWorkbookPage.NewClassFolderDialog.description", projpath.toString())); 
		if (dialog.open() == Window.OK) {
			IFolder folder= dialog.getFolder();
			return new CPListElement[] { newCPLibraryElement(folder) };
		}
		return null;
	}
			
			
	private CPListElement[] openClassFolderDialog(CPListElement existing) {
		if (existing == null) {
			IPath[] selected= BuildPathDialogAccess.chooseClassFolderEntries(getShell(), fCurrJProject.getPath(), getUsedContainers(existing));
			if (selected != null) {
				ArrayList res= new ArrayList();
				for (int i= 0; i < selected.length; i++) {
					IPath curr= selected[i];
					IResource resource= fWorkspaceRoot.findMember(curr);
					if (resource instanceof IContainer) {
						res.add(newCPLibraryElement(resource));
					}
				}
				return (CPListElement[]) res.toArray(new CPListElement[res.size()]);
			}
		} else {