Determine when JFrame resized

Source code below will show you, how to determine when JFrame re sized.

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COMPLETE SOURCE CODE FOR : DetermineWhenAJFrameIsResized.java
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import javax.swing.JFrame;
import javax.swing.JOptionPane;

import java.awt.event.ComponentEvent;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentListener;

public class DetermineWhenAJFrameIsResized extends JFrame
{
//Create ComponentListener that will listen when JFrame is resizing
ComponentListener cl=new ComponentAdapter()
{
 public void componentResized(ComponentEvent event)
 {
  JOptionPane.showMessageDialog(null,"New size with :\n"+"WIDTH : "+getSize().width+"\n"+"HEIGHT : "+getSize().height);
 }
};

public DetermineWhenAJFrameIsResized()
{
 super("TRY RESIZE ME");

 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 setSize(300,300);
 setVisible(true);

 //Add ComponentListener to JFrame
 addComponentListener(cl);
}

public static void main(String[]args)
{
 DetermineWhenAJFrameIsResized dwajfir=new DetermineWhenAJFrameIsResized();
}
}

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JUST COMPILE AND EXECUTE IT
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