Get last selected JRadioButton

Complete source code below will show you, how to get last selected JRadioButton when we click on other JRadioButton. I hope you will understand what i want to tell you, or you can try to compile and execute source code below.

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COMPLETE SOURCE CODE FOR : GetLastSelectedJRadioButton.java
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import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

public class GetLastSelectedJRadioButton implements ItemListener
{
JRadioButton jrd1=new JRadioButton("a");
JRadioButton jrd2=new JRadioButton("b");
JRadioButton jrd3=new JRadioButton("c");
JRadioButton jrd4=new JRadioButton("d");

JRadioButton last=null;

ButtonGroup bg=new ButtonGroup();

JFrame myFrame=new JFrame("Get last selected JRadioButton");

public GetLastSelectedJRadioButton()
{
 jrd1.addItemListener(this);
 jrd2.addItemListener(this);
 jrd3.addItemListener(this);
 jrd4.addItemListener(this);

 bg.add(jrd1);
 bg.add(jrd2);
 bg.add(jrd3);
 bg.add(jrd4);

 myFrame.getContentPane().setLayout(new GridLayout(4,1));

 myFrame.getContentPane().add(jrd1);
 myFrame.getContentPane().add(jrd2);
 myFrame.getContentPane().add(jrd3);
 myFrame.getContentPane().add(jrd4);

 myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 myFrame.setSize(400,400);
 myFrame.setLocationRelativeTo(null);
 myFrame.setVisible(true);
}

public void itemStateChanged(ItemEvent event)
{
 JRadioButton temp=(JRadioButton)event.getItem();

 if(event.getStateChange()==ItemEvent.DESELECTED)
 {
  last=temp;
 }
 else if(event.getStateChange()==ItemEvent.SELECTED)
 {
  if(last!=null)
  {
   JOptionPane.showMessageDialog(myFrame,"LAST : "+last.getText(),"Last",JOptionPane.INFORMATION_MESSAGE);
  }
 }
}

public static void main(String[]args)
{
 GetLastSelectedJRadioButton glsjrb=new GetLastSelectedJRadioButton();
}
}

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JUST COMPILE AND EXECUTE IT
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