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/PackageExplorerPart.java
newSelection= new StructuredSelection(element);
							fViewer.setSelection(newSelection);
						}
					}
				} finally {
					fViewer.addSelectionChangedListener(fSelectionListener);
				}
			}
			return true;
		}
		return false;
	}
	
	private boolean isOnClassPath(IFile file) {
		IJavaProject jproject= JavaCore.create(file.getProject());
		try {
			return jproject.isOnClasspath(file);
		} catch (JavaModelException e) {
			
		}
		return false;
	}
	/**
	 * Returns the element's parent.
	 * 
	 * @return the parent or <code>null</code> if there's no parent
	 */
	private Object getParent(Object element) {
		if (element instanceof IJavaElement)
			return ((IJavaElement)element).getParent();