CODE EXAMPLE FOR JAVA

java actionlistener

import javax.swing.*;
import java.awt.event.*;

public class JButtonExample
{
  public static void main(String[] args) 
  {
    JFrame frame = new JFrame("ActionListener Example");
    JButton btn = new JButton("Click here");
    btn.setBounds(70,80,100,30);
    //Change button text on click
    btn.addActionListener(new ActionListener() {
       public void actionPerformed(ActionEvent ae) {
                      btn.setText("OK");
       }
    });
    frame.add(btn);
    frame.setSize(250,250);
    frame.setLayout(null);
    frame.setVisible(true);  
  }
}