Bug 73984 Editing user library jar path after path change does not work [build path]
1) Create a directory containing jar file 2) Add this jar file to a new user library 3) Rename directory from 1) 4) Update the path to jar file in user libraries (select old jar reference, select new location in browser, open -> path is not updated, but old path is still used
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/UserLibraryPreferencePage.java
boolean contained= oldNames.remove(element.getName());
			if (!contained) {
				newEntries.add(element);
			}
		}	
		
		int len= nExisting + oldNames.size();
		monitor.beginTask(PreferencesMessages.getString("UserLibraryPreferencePage.operation"), len); 
		MultiStatus multiStatus= new MultiStatus(JavaUI.ID_PLUGIN, IStatus.OK, PreferencesMessages.getString("UserLibraryPreferencePage.operation.error"), null); 
		
		ClasspathContainerInitializer initializer= JavaCore.getClasspathContainerInitializer(JavaCore.USER_LIBRARY_CONTAINER_ID);
		IJavaProject jproject= fDummyProject;
		
		IJavaProject[] projectInit= new IJavaProject[] { jproject };
		IClasspathContainer[] containerInit= new IClasspathContainer[] { null };
		
		ArrayList paths= new ArrayList();
		ArrayList urls= new ArrayList();
		
		for (int i= 0; i < nExisting; i++) {
			CPUserLibraryElement element= (CPUserLibraryElement) list.get(i);
			IPath path= element.getPath();
			if (newEntries.contains(element) || element.hasChanges(JavaCore.getClasspathContainer(path, jproject))) {
				IClasspathContainer updatedContainer= element.getUpdatedContainer();
				try {
					initializer.requestClasspathContainerUpdate(path, jproject, updatedContainer);
					containerInit[0]= updatedContainer;
					JavaCore.setClasspathContainer(path, projectInit, containerInit, null);  
				} catch (CoreException e) {
					multiStatus.add(e.getStatus());