Action Event Handeler in Java with Program

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

import java.text.DateFormat;
import java.util.Date;
import java.util.Locale;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class ActionEventExample extends JFrame implements ActionListener {

private JList list;
private DefaultListModel model;

public ActionEventExample() {

initUI();

}

public final void initUI() {

JPanel panel = new JPanel();
panel.setLayout(null);

model = new DefaultListModel();
list = new JList(model);
list.setBounds(150, 30, 220, 150);

JButton okButton = new JButton("Ok");
okButton.setBounds(30, 35, 80, 25);

okButton.addActionListener(this);

panel.add(okButton);
panel.add(list);
add(panel);

setTitle("Event Example");
setSize(420, 250);
setLocationRelativeTo(null);
setDefaultCloseOperation(EXIT_ON_CLOSE);

}

public void actionPerformed(ActionEvent e) {

Locale locale = Locale.getDefault();
Date date = new Date(e.getWhen());
String s = DateFormat.getTimeInstance(DateFormat.SHORT, locale).format(
date);

if (!model.isEmpty()) {
model.clear();
}

if (e.getID() == ActionEvent.ACTION_PERFORMED) {
model.addElement(" Event Id: ACTION_PERFORMED");
}

model.addElement(" Time: " + s);

String source = e.getSource().getClass().getName();
model.addElement(" Source: " + source);

int mod = e.getModifiers();

StringBuffer buffer = new StringBuffer(" Modifiers: ");

if ((mod & ActionEvent.ALT_MASK) > 0) {
buffer.append("Alt ");
}

if ((mod & ActionEvent.SHIFT_MASK) > 0) {
buffer.append("Shift ");
}

if ((mod & ActionEvent.META_MASK) > 0) {
buffer.append("Meta ");
}

if ((mod & ActionEvent.CTRL_MASK) > 0) {
buffer.append("Ctrl ");
}

model.addElement(buffer);
}

public static void main(String[] args) {

SwingUtilities.invokeLater(new Runnable() {

public void run() {

ActionEventExample ex = new ActionEventExample();
ex.setVisible(true);

}
});
}
}