Creating an offscreen frame in Java (or: how to avoid a blank menu on a Mac, when all application windows are closed)?

Question

I am making a Mac application, and I want my menu bar to look right.

Any Mac user knows the menu bar should be in the top screen menu. Setting apple.laf.useSc

Answer 1

This is a comment to trashgod's answer. It's too big so I have to move it here >.<

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More problems!

I'm getting 2 errors:

line 23: The method itemStateChanged(ItemEvent) of type new ItemListener(){} must override a superclass method

line 50:The method run() of type new Runnable(){} must override a superclass method

Any help? I've never encountered this before. I don't know what it means.

EDIT: I have more problems! I need the offscreen window to be visible while it is offscreen for it to produce a menu to move to the screen menu bar. When I use the code

offScreen = new JFrame("WTF?!  You can see me?");
offScreen.setSize(400,300);
offScreen.setLocation(0, java.awt.Toolkit.getDefaultToolkit().getScreenSize().height+50);
System.out.println(offScreen.getLocation());
offScreen.setVisible(true);
System.out.println(offScreen.getLocation());

I get the output:

java.awt.Point[x=0,y=1100]
java.awt.Point[x=0,y=961]

It moves it back once it's made visible again!

I've searched for ages and I can't find anything.