Listens for window iconify and deiconify events, so that it can stop the animation when the window isn't visible. : Window Event « Swing Event « Java Tutorial

1. Java Tutorial
2. Swing Event
3. Window Event

import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;

import javax.swing.JFrame;

public class UsingWindowListener {
  public static void main(String[] args) {
    JFrame aWindow = new JFrame("This is the Window Title");
    aWindow.setBounds(50, 100, 300, 300);
    aWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    aWindow.addWindowListener(new WindowListener() {
      public void windowIconified(WindowEvent e) {
        System.out.println(e);
      }

      public void windowDeiconified(WindowEvent e) {

      }

      public void windowOpened(WindowEvent e) {
      }

      public void windowClosing(WindowEvent e) {
      }

      public void windowClosed(WindowEvent e) {
      }

      public void windowActivated(WindowEvent e) {
      }

      public void windowDeactivated(WindowEvent e) {
      }

    });

    aWindow.setVisible(true);
  }
}

15.41.Window Event
	15.41.1.	The event IDs for the WindowEvent class
	15.41.2.	Making a Window Handle its Own Events
	15.41.3.	The WindowListener Interface: events reflecting changes in the state of a window
	15.41.4.	Using WindowListener
	15.41.5.	Using Adapter Classes
	15.41.6.	Listens for window iconify and deiconify events, so that it can stop the animation when the window isn't visible.
	15.41.7.	WindowListener, WindowFocusListener, WindowStateListener
	15.41.8.	extends WindowAdapter
	15.41.9.	Handle a window closing event
	15.41.10.	Setting the Initial Focused Component in a Window
	15.41.11.	int java.awt.event.WindowEvent.WINDOW_OPENED