FULL PRODUCT VERSION :
java version "1.7.0_04-ea"
Java(TM) SE Runtime Environment (build 1.7.0_04-ea-b19)
Java HotSpot(TM) 64-Bit Server VM (build 23.0-b20, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Mac OS X 10.7.3

A DESCRIPTION OF THE PROBLEM :
When the ScreenMenuBar is activated using System.setProperty("apple.laf.useScreenMenuBar", "true"); and the registered Accelerator Key for a JMenuItem is pressed, the ActionListener is called twice.


REGRESSION. Last worked in version 6u31

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Activate the usage of the Screen Menu Bar
System.setProperty("apple.laf.useScreenMenuBar", "true");

Create a JFrame with a JMenuBar, JMenu and a JMenuItem and register a hotkey to the JMenuItem using setAccelerator and add an ActionListener.

Start the test application and press the Hotkey.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Having the ActionListener called once per pressed hotkey.
ACTUAL -
The ActionListener its called twice.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.lang.reflect.InvocationTargetException;

import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.KeyStroke;
import javax.swing.SwingUtilities;

public class Test extends JFrame {

public Test() {
JMenuBar menuBar = new JMenuBar();
JMenu fileMenu = new JMenu("File");
JMenuItem openItem = new JMenuItem("Open");
openItem.setAccelerator(KeyStroke.getKeyStroke('O', Toolkit.getDefaultToolkit().getMenuShortcutKeyMask()));
openItem.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
System.out.println("i was called");
}
});
fileMenu.add(openItem);
menuBar.add(fileMenu);
setJMenuBar(menuBar);
pack();
setVisible(true);
}

public static void main(String[] args) throws InvocationTargetException, InterruptedException {
System.setProperty("apple.laf.useScreenMenuBar", "true");
SwingUtilities.invokeAndWait(new Runnable() {

@Override
public void run() {
new Test();
}
});
}
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Do not use the ScreenMenuBar.