I'm capturing a screenshot image of a JFrame via a "double buffering" approach, per below:

public BufferedImage getScreenshot() {      
  java.awt.Dimension dim = this.getPreferredSize();         
  BufferedImage image = new BufferedImage(dim.width, dim.height, BufferedImage.TYPE_INT_RGB);            
  this.paint(image.getGraphics());      
  return image;     
}

where this extends JFrame. The image that I get has a blank strip along the top where the title bar was. What's the most straightforward way to capture an image of the contents of the JFrame without the extra space allocated for the title bar?