Thread: How to create transparent JProgress Bar or customize JProgress Bar?

Here is a way to make a transparent popup menu. You can modify this code to work with other Swing components such as the JProgress bar.

import javax.swing.*;
import java.awt.*;
 
class TransparentPopupMenu extends JPopupMenu {
     public TransparentPopupMenu() { 
          super();
          setOpaque(false); 
     } 
}
 
class TransparentMenuItem extends JMenuItem{
     public TransparentMenuItem(String text) { 
          super(text);
          setOpaque(false); 
     } 
 
     public void paint(Graphics g) { 
          Graphics2D g2 = (Graphics2D) g.create(); 
          g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.5f)); 
          super.paint(g2); 
          g2.dispose(); 
     } 
}

The transparency level is set here:

g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, [B]0.5f[/B]));

0.0f means 100% transparent (you will not see it)
0.5f means 50% transparent
1.0f means 0% transparent (Not transparent at all)

Also look here:

Hacking Swing: Translucent Windows | O'Reilly Media