windowMonitor.java

import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JFrame;

public class Main extends JFrame {
  public Main() {
    setSize(300, 300);
    setTitle("Window Listener");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    this.addWindowListener(new WindowAdapter() {
      public void windowOpened(WindowEvent e) {
        System.out.println("Window Opened Event");
      }

      public void windowClosing(WindowEvent e) {
        System.out.println("Window Closing Event");
      }

      public void windowClosed(WindowEvent e) {
        System.out.println("Window Close Event");
      }

      public void windowIconified(WindowEvent e) {
        System.out.println("Window Iconified Event");
      }

      public void windowDeiconified(WindowEvent e) {
        System.out.println("Window Deiconified Event");
      }

      public void windowActivated(WindowEvent e) {
        System.out.println("Window Activated Event");
      }

      public void windowDeactivated(WindowEvent e) {
        System.out.println("Window Deactivated Event");
      }

      public void windowStateChanged(WindowEvent e) {
        System.out.println("Window State Changed Event");
      }

      public void windowGainedFocus(WindowEvent e) {
        System.out.println("Window Gained Focus Event");
      }

      public void windowLostFocus(WindowEvent e) {
        System.out.println("Window Lost Focus Event");
      }
    });
  }

  public static void main(String[] args) {
    new Main().setVisible(true);
  }
}