UIManager.put("PopupMenuUI","CustomPopupMenuUI");
JFrame frame = new JFrame();
JMenuBar mb = new JMenuBar();
frame.setJMenuBar(mb);
JMenu menu = new JMenu("File");
mb.add(menu);
menu.add(new JMenuItem("Open"));
menu.add(new JMenuItem("Save"));
menu.add(new JMenuItem("Close"));
menu.add(new JMenuItem("Exit"));
menu = new JMenu("Edit");
mb.add(menu);
menu.add(new JMenuItem("Cut"));
menu.add(new JMenuItem("Copy"));
menu.add(new JMenuItem("Paste"));
menu.add(new JMenuItem("Paste Special.."));
frame.getContentPane().setLayout(new BorderLayout());
frame.getContentPane().add("North",new JButton("Button"));
frame.getContentPane().add("Center",new JLabel("a label"));
frame.getContentPane().add("South",new JCheckBox("checkbox"));
frame.pack();
frame.setSize(200,150);
frame.show();