To Capture screen shots using Java

import java.awt.Dimension;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import java.io.File;
public void captureScreen(String fileName) throws Exception 
{
    Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();   
Rectangle screenRectangle = new Rectangle(screenSize);  
 Robot robot = new Robot();  
 BufferedImage image = robot.createScreenCapture(screenRectangle);  
 ImageIO.write(image, "png", new File(fileName)); 
}