Bug 31374 Package Explorer does not show children of linked directories
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/StandardJavaElementContentProvider.java
if (((IParent)element).hasChildren())
					return true;
			} catch(JavaModelException e) {
				return true;
			}
		}
		Object[] children= getChildren(element);
		return (children != null) && children.length > 0;
	}
	 
	/* (non-Javadoc)
	 * Method declared on ITreeContentProvider.
	 */
	public Object getParent(Object element) {
		if (!exists(element))
			return null;
		return internalGetParent(element);			
	}
	
	private Object[] getPackageFragments(IPackageFragmentRoot root) throws JavaModelException {
		IJavaElement[] fragments= root.getChildren();
		Object[] nonJavaResources= root.getNonJavaResources();
		if (nonJavaResources == null)
			return fragments;
		return concatenate(fragments, nonJavaResources);
	}
	
	protected Object[] getPackageFragmentRoots(IJavaProject project) throws JavaModelException {
		if (!project.getProject().isOpen())
			return NO_CHILDREN;