Bug 31683 Show In doesn't work for class file in rt.jar
I20030611 - create Test project that uses Jar container - open NumberFormat.class - activate Show In... and choose Package Explorer Observe: NumberFormat.class doesn't get revealed.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerContentProvider.java
} else {
				children= super.getChildren(parentElement);
			}
	
			if (parentElement instanceof IJavaProject) {
				IJavaProject project= (IJavaProject)parentElement;
				return rootsAndContainers(project, children);
			}
			else
				return children;
		} catch (CoreException e) {
			return NO_CHILDREN;
		}
	}
	private Object[] rootsAndContainers(IJavaProject project, Object[] roots) { 
		List result= new ArrayList(roots.length);
		Set containers= new HashSet(roots.length);
		for (int i= 0; i < roots.length; i++) {
			if (roots[i] instanceof IPackageFragmentRoot) {
				IPackageFragmentRoot root= (IPackageFragmentRoot)roots[i];
				IClasspathEntry entry= null;
				try {
					entry= root.getRawClasspathEntry();
				} catch (JavaModelException e) {
					continue;
				}
				if (entry != null && entry.getEntryKind() == IClasspathEntry.CPE_CONTAINER) 
					containers.add(entry);
				else
					result.add(root);