Code Samples from the Java Developers Almanac 2000

 drawGraphic1(g2d);
     
 // Set alpha.  0.0f is 100% transparent and 1.0f is 
 // 100% opaque.
 float alpha = .7f;
 g2d.setComposite(
   AlphaComposite.getInstance(
     AlphaComposite.SRC_OVER, alpha));
    
 drawGraphic2(g2d);