Q:

JFrame (being fullscreened) background color not changing

im using 
getContentPane().setBackground(Color.PINK);

to set the background of a JFrame to the color pink. this JFrame is being fullscreened using a GraphicsDevice. the color of the background is not changing. any help?
fullscreen code:
public static void main(String... args) {
     DisplayMode dMode = new DisplayMode(800, 600, 16, DisplayMode.REFRESH_RATE_UNKNOWN);
     GameMain game = new GameMain();
     game.run(dMode);

 }

 public void run(DisplayMode dMode) {
     getContentPane().setBackground(Color.PINK);
     setForeground(Color.WHITE);
     setFont(new Font("Arial", Font.PLAIN, 24));

     Screen s = new Screen();
     try {
         s.setFullScreen(dMode, this);
         try {
             Thread.sleep(5000);
         } catch(Exception e) { }
     } finally {
         s.restoreScreen();
     }

     }
 public void setFullScreen(DisplayMode dMode, JFrame window) {
    window.setUndecorated(true);
    window.setResizable(false);
    gDevice.setFullScreenWindow(window);

    if(dMode != null && gDevice.isDisplayChangeSupported()) {
        try {
            gDevice.setDisplayMode(dMode);
        } catch(Exception e) { }
    }
}

A:

This works fine for me...
public class TestFullScreen {

    public static void main(String[] args) {

        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {

                FullFrame frame = new FullFrame();
                frame.setUndecorated(true);
                frame.getContentPane().setBackground(Color.PINK);

                GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
                GraphicsDevice[] gs = ge.getScreenDevices();

                gs[0].setFullScreenWindow(frame);

            }
        });

    }

    public static class FullFrame extends JFrame {

        public FullFrame() {
            super();

            addMouseListener(new MouseAdapter() {
                @Override
                public void mouseClicked(MouseEvent e) {
                    System.exit(0);
                }
            });

        }
    }
}

I even set moved the setBackground call after the setFullScreenWindow call.
Make sure you don't have anything on the content pane that might be taking up the full space and that the content pane hasn't been changed.

