给看看java里的一个小错误.

我已运行过的代码：

import java.awt.*;
import java.awt.event.*;
public class TestButton {
private Frame f;

private Button b;

public TestButton() {
f = new Frame("Test");
b = new Button("Press me!");
b.setActionCommand("ButtonPressed");
}

public void launchFrame() {
b.addActionListener(new ButtonHandler());
f.add(b, BorderLayout.CENTER);
f.pack();
f.setVisible(true);
}

public static void main(String[] args) {
TestButton tb = new TestButton();
tb.launchFrame();
}
}

class ButtonHandler implements ActionListener {
public void actionperformed(ActionEvent e) {
System.out.println("Action occurred");
System.out.println("Button's command is:" + e.getActionCommand());
}

public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method