import java.awt.event.*;                                  
import javax.swing.*;                                     
public class TickTock
{
    public static void main(String[] args)
    {
        // create a timer that calls the Ticker class
        // at one second intervals
        Timer t = new Timer(1000, new Ticker());          
        t.start();                                       
        // display a message box to prevent the
        // program from ending immediately
        JOptionPane.showMessageDialog(null, "Click OK to exit program");
    }
}

class Ticker implements ActionListener                   

{
    private boolean tick = true;                         
    public void actionPerformed(ActionEvent event)       
    {
        if (tick)
        {
            System.out.println("Tick...");               
        }
        else
        {
            System.out.println("Tock...");               
        }
        tick = !tick;                                    
    }
}