This program demonstrates the use of inner classes : Inner Class « Class « Java

This program demonstrates the use of inner classes

   This program is a part of the companion code for Core Java 8th ed.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <>.

import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Date;

import javax.swing.JOptionPane;
import javax.swing.Timer;

 * This program demonstrates the use of inner classes.
 * @version 1.10 2004-02-27
 * @author Cay Horstmann
public class InnerClassTest
   public static void main(String[] args)
      TalkingClock clock = new TalkingClock(1000, true);

      // keep program running until user selects "Ok"
      JOptionPane.showMessageDialog(null, "Quit program?");

 * A clock that prints the time in regular intervals.
class TalkingClock
    * Constructs a talking clock
    * @param interval the interval between messages (in milliseconds)
    * @param beep true if the clock should beep
   public TalkingClock(int interval, boolean beep)
      this.interval = interval;
      this.beep = beep;

    * Starts the clock.
   public void start()
      ActionListener listener = new TimePrinter();
      Timer t = new Timer(interval, listener);

   private int interval;
   private boolean beep;

   public class TimePrinter implements ActionListener
      public void actionPerformed(ActionEvent event)
         Date now = new Date();
         System.out.println("At the tone, the time is " + now);
         if (beep) Toolkit.getDefaultToolkit().beep();


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