java核心技术得代码自己照着输一遍有错误 错误提示在 ActionListener listener=new TimePrinter();

Question

package diliuzhang;

import java.awt.*;

import java.awt.event.*;

import java.util.*;

import javax.swing.*;

import javax.swing.Timer;

public class TimerTest {

public static void main(String[] args) {

ActionListener listener=new TimePrinter();

Timer t=new Timer(10000,listener);

t.start();

JOptionPane.showMessageDialog(null, "Quit program?");

System.exit(0);

}

class TimePrinter implements ActionListener{

public void actionPerformed(ActionEvent event) {

System.out.println("At the tone,tjis time is"+new Date());

Toolkit.getDefaultToolkit().beep();

}

}

}