import java.awt.event.ActionEvent; 
import javax.swing.*; 

public class JMenuBarTest { 
  public static void main(String [] args) { 
    System.setProperty("apple.laf.useScreenMenuBar", "true"); 
     
    final JFrame frame = new JFrame(); 
    JMenuItem menuItem = new JMenuItem(new AbstractAction("Hello") { 
        public void actionPerformed(ActionEvent ev) { 
          JOptionPane.showMessageDialog(frame, "Hello"); 
        } 
      }); 

    JMenuBar menuBar = new JMenuBar(); 
    frame.setJMenuBar(menuBar); 
    JMenu fileMenu = new JMenu("File"); 
    menuBar.add(fileMenu); 
    fileMenu.add(menuItem); 
    frame.setVisible(true); 
  } 
}