Java JFrame process window event

import java.awt.event.WindowEvent;

import javax.swing.JFrame;

public class Main extends JFrame {
  public Main(String title) {
    setTitle(title); /*from  www  . ja  v  a2 s. c o m*/
    //setDefaultCloseOperation(EXIT_ON_CLOSE);
    enableEvents(java.awt.AWTEvent.WINDOW_EVENT_MASK);
  }
  protected void processWindowEvent(WindowEvent e) {
    if (e.getID() == WindowEvent.WINDOW_CLOSING) {
      System.out.println(WindowEvent.WINDOW_CLOSING);
      dispose(); 
      System.exit(0);
    }
    super.processWindowEvent(e); // Pass on the event
  }
  public static void main(String[] a) {
    Main window = new Main("demo2s.com");
    window.setBounds(30, 30, 300, 300);
    window.setVisible(true);
  }
}