How to create a transparent/translucent Java JFrame on Mac OS X

I just tried a quick test of transparency/translucency on Mac OS X using Java, and in short, here is the source code I used to create a transparent/translucent Java JFrame on Mac OS X 10.9:

package demo;

import javax.swing.*;
import java.awt.BorderLayout;
import java.awt.Dimension;

/**
 * Creates a transparent/translucent Java JFrame on Mac OS X.
 * @author alvin alexander, http://alvinalexander.com
 */
public class MacTranslucentFrame
{
    public static void main(String[] args)
    {
        new MacTranslucentFrame();
    }

    public MacTranslucentFrame()
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                JFrame editorFrame;
                editorFrame = new JFrame("Java Mac OS X Translucency Demo");
                editorFrame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

                // this is what sets the transparency/translucency on Mac OS X
                editorFrame.getRootPane().putClientProperty("Window.alpha", new Float(0.2f));

                editorFrame.setUndecorated(true);
                editorFrame.setPreferredSize(new Dimension(1200, 900));
                editorFrame.setMinimumSize(new Dimension(1200, 900));
                editorFrame.pack();
                editorFrame.setLocation(10,10);
                editorFrame.setVisible(true);
            }
        });
    }
}

This code creates a 1200x900 pixel Java JFrame that is 80% transparent, letting you see your desktop and anything else that is behind it.