event handling in Java

import javax.swing.*;

import java.awt.event.*;

public class SimpleGui implements ActionListener {
JButton button;

public static void main(String[] args) {
SimpleGui gui = new SimpleGui();
gui.go();
}

public void go() {
JFrame frame = new JFrame();
button = new JButton("click me");

button.addActionListener(this);

frame.getContentPane().add(button);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 300);
frame.setVisible(true);
}

@Override
public void actionPerformed(ActionEvent event) {
// TODO Auto-generated method stub
button.setText("I've been clicked!");
}

}