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
List res= new ArrayList();
		List cplist= fLibrariesList.getElements();
		for (int i= 0; i < cplist.size(); i++) {
			CPListElement elem= (CPListElement)cplist.get(i);
			if (elem.getEntryKind() == IClasspathEntry.CPE_LIBRARY && (elem != existing)) {
				IResource resource= elem.getResource();
				if (resource instanceof IFile) {
					res.add(resource.getFullPath());
				}
			}
		}
		return (IPath[]) res.toArray(new IPath[res.size()]);
	}	
	
	private CPListElement newCPLibraryElement(IResource res) {
		return new CPListElement(fCurrJProject, IClasspathEntry.CPE_LIBRARY, res.getFullPath(), res);
	}
	private CPListElement[] openExtJarFileDialog(CPListElement existing) {
		if (existing == null) {
			IPath[] selected= BuildPathDialogAccess.chooseExternalJAREntries(getShell());
			if (selected != null) {
				ArrayList res= new ArrayList();
				for (int i= 0; i < selected.length; i++) {
					res.add(new CPListElement(fCurrJProject, IClasspathEntry.CPE_LIBRARY, selected[i], null));
				}
				return (CPListElement[]) res.toArray(new CPListElement[res.size()]);
			}
		} else {
			IPath configured= BuildPathDialogAccess.configureExternalJAREntry(getShell(), existing.getPath());
			if (configured != null) {