Como mostrar o JMenuBar no JDesktopPane?

import javax.swing.JApplet;
import javax.swing.JDesktopPane;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;

public class MainFrame extends JApplet{

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	public void init(){
		
		//Barra Menu
		JMenuBar menuBar = new JMenuBar();
		JMenu menu1 = new JMenu("menu1");
		menu1.add(new JMenuItem("Teste"));
		
		JDesktopPane desktopPane = new JDesktopPane();
		
		MenusInternalFrame caixasItens = new MenusInternalFrame();

		//add menu ao painel
		menuBar.add(menu1);
		
		//add objetos no desktop
		desktopPane.add(menuBar);
		desktopPane.add(caixasItens);
		
		this.getContentPane().add(desktopPane);
		this.setSize(800,600);
		
	}
}