Just use Swing. Then you get automatic double buffering.

No more need for all that low-level mucking about.

What Jon said or create a BufferedImage and its Graphics object as class
variables, render everything to the BufferedImage first, and then copy the
image to the actual drawing surface using Graphics.drawImage().

*
* @(#)DoubleBufferPanel.java        1.2 97/01/14 Jeff Dinkins
*
* Copyright (c) 1995-1997 Sun Microsystems, Inc. All Rights Reserved.
*
*/

package actual;

import java.awt.*;
import java.applet.*;

public class DoubleBufferPanel extends Panel {

 Image offscreen;

 /**
  * null out the offscreen buffer as part of invalidation
  */
 public void invalidate() {
     super.invalidate();
     offscreen = null;
 }

 /**
  * override update to *not* erase the background before painting

  */
 public void update(Graphics g) {
     paint(g);
 }

 /**
  * paint children into an offscreen buffer, then blast entire image
  * at once.
  */
 public void paint(Graphics g) {
     if(offscreen == null) {
        offscreen = createImage(getSize().width, getSize().height);
     }

     Graphics og = offscreen.getGraphics();
     og.setClip(0,0,getSize().width, getSize().height);
     super.paint(og);
     g.drawImage(offscreen, 0, 0, null);

     og.dispose();
 }
}

same way.

____________

http://reader.imagero.com the best java image reader.

Thanks for all answers.

Unfortunately I still can't get it properly. The problem is:
I'm painting on a JComponent, there's an image in the background and
there are already several objects ( circle, etc. ) drawn on that background.

I don't have the coordinates of these objects any more, which means I can't
use repaint(), etc. . I can't clear the whole image. ( I don't use paint(),
update() .. ).

Is there a method which gives me the current content of the JComponent and
allows me, unlike this.getGraphics() , to render on a copied version of this
content
first before I use this.getGraphics.draw( ... )  to finally put it onto the
screen?

Does somebody know where my problem is / what I'm doing wrong?

Cheers