Show PopupMenu in JMenuItem

Question

I want to show the popupmenu when users do the right click on the
menuitem to do something like the mozilla or internet explorer
Favorites menu which can be do right click to show the popup.
I tried this, but i always have the following problems:
java.lang.NullPointerException
at javax.swing.plaf.basic.BasicPopupMenuUI$MouseGrabber.grabContainer(Unknown Source)
at javax.swing.plaf.basic.BasicPopupMenuUI$MouseGrabber.requestAddGrab(Unknown Source)
at javax.swing.plaf.basic.BasicPopupMenuUI$MouseGrabber.stateChanged(Unknown Source)
at javax.swing.MenuSelectionManager.fireStateChanged(Unknown Source)
at javax.swing.MenuSelectionManager.setSelectedPath(Unknown Source)
at javax.swing.JPopupMenu.setVisible(Unknown Source)
at javax.swing.JPopupMenu.show(Unknown Source)
at test.jessy.menu.TestSimplePopup$1.mousePressed(TestSimplePopup.java:34)
This is my test code, I can compile and run it. But the error occurs
when I do the right mouse click on the "http://java.sun.com" jmenuitem
of this code. Aims to show the popup window and this menuitem still
stay show. Thanks for your help.
==============================================================
public class TestSimplePopup extends JFrame{
JPopupMenu popupMenu;
public TestSimplePopup() {
super();
//create popupmenu.
popupMenu = new JPopupMenu();
popupMenu.add( new JMenuItem("delete this link"));
popupMenu.add( new JMenuItem("go to this link"));
//create menubar.
JMenuBar menuBar = new JMenuBar();
//create favoritemenu.
JMenu favoriteMenu = new JMenu("Favorite");
JMenuItem link1 = new JMenuItem("http://java.sun.com");
link1.addMouseListener(new MouseAdapter(){
public void mousePressed(MouseEvent e) {
if( SwingUtilities.isRightMouseButton(e) ){
//right-click
popupMenu.show(e.getComponent(), e.getX(), e.getY());
} else {
System.out.println( "left click=" + e.getSource() );
favoriteMenu.add( link1 );
menuBar.add( favoriteMenu );
setJMenuBar( menuBar );
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(400, 400);
show();
public static void main(String[] args) {
new TestSimplePopup();
==============================================================

Answer 1

First:
please use code-tags when posting code. You should now this (its your 9th post after all).
Second:
I believe the NullPointerException is thrown because the popupMenu itself does not have a Window ancestor (I debugged your code). How to set the ancestor of your popupMenu to your JFrame I am not sure. JFrame has an add(PopupMenu) but not add(JPopupMenu).
Perhaps someone else can help you further.