Create an anonymous class : Anonymous Class « Object Oriented « SCJP

1. SCJP
2. Object Oriented
3. Anonymous Class

Anonymous classes can be declared to extend another class or to implement a single interface. 


import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;

public class MainClass {
  public static void main(String[] argv) {
    JButton theButton = new JButton();

    theButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        System.out.println("The action has occurred");
      }
    });

  }
}