import java.awt.event.*;

import javax.swing.*;

public class Exercice0 {

  public static void main(String[] args) {
    final JFrame frame=new JFrame();
    //frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    
    WindowListener l=new WindowAdapter() {
      public void windowClosing(WindowEvent e) {
        JOptionPane.showMessageDialog(frame, "au revoir", "fermeture", JOptionPane.WARNING_MESSAGE);
        //frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      }
    };
    frame.addWindowListener(l);
    
    frame.setSize(400,300);
    frame.show();
  }
}