Java GUI components can be dumped to standard image file using code
exampled below. However, the outermost frame, including title header,
of Frame or JFrame can't be captured through this method because they
aren't rendered by Java but the native windowing system. I'd like to
know a workaround, if any.
<code>
 public static void writeComponentToFile
  (Component comp, String fileName){
                   //output file
   String[] temp = fileName.split("\\.");
   String ext = temp[temp.length - 1];
   
   BufferedImage bImage
    = new BufferedImage(comp.getWidth(), comp.getHeight(),
                         BufferedImage.TYPE_INT_RGB);
   
   Graphics g = bImage.getGraphics();
   comp.paint(g);
   
   try{
     File file = new File(fileName);
     if (ext.equals("png")){
       ImageIO.write(rImage, "png", file);
     }  
     else if (ext.equals("jpg")){
       ImageIO.write(rImage, "jpg", file);
     }
     else{
       System.err.println("Unsupported format: " + ext);
       System.err.println("We only support .jpg and .png files);
     }
   }
   catch(Exception e){
     e.printStackTrace();
   }
 }
</code