Determine when JFrame resized

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

***********************************************************************
COMPLETE SOURCE CODE FOR : DetermineWhenAJFrameIsResized.java
***********************************************************************

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();
}
}

***********************************************************************
JUST COMPILE AND EXECUTE IT
***********************************************************************

How to know when a component resized

We use button as component in this example.

****************************************************************
COMPLETE SOURCE CODE FOR : HowToKnowWhenComponentResize.java
****************************************************************

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;

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

import java.awt.Component;

public class HowToKnowWhenComponentResize
{
 JFrame b=new JFrame("TRY RESIZE ME");
 
 JButton d=new JButton("MONSTER");
 
 public HowToKnowWhenComponentResize()
 {
  ComponentListener cl=new ComponentAdapter()
  {
   public void componentResized(ComponentEvent evt)
   {
    Component temp=(Component)evt.getSource();
    int currentWidth=temp.getSize().width;
    int currentHeight=temp.getSize().height;
    JOptionPane.showMessageDialog(null,"SIZE OF COMPONENT IS CHANGE\nMONSTER WIDTH NOW : "+currentWidth+"\nMONSTER HEIGHT NOW : "+currentHeight,"MONSTER'S SIZE",JOptionPane.INFORMATION_MESSAGE);
   }
  };
  
  d.addComponentListener(cl);
  b.add(d);
  
  b.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  b.setSize(400,100);
  b.setVisible(true);
 }
 
 public static void main(String[]args)
 {
  HowToKnowWhenComponentResize myObject=new HowToKnowWhenComponentResize();
 }
}

****************************************************************
JUST COMPILE AND EXECUTE IT
****************************************************************