How to prevent timer from repeats

Question

hello there i've made a countdown timer
and i want it when it finishes counting till 0 not repeating from the beginning but do some action
i uesd the method
timer.setRepeats(false);but it stops the timer from counting
i'm using javax.swing.timer;
and here is the code:
import java.math.*;
import java.util.*;
import java.text.*;
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class Timer1 extends JFrame {
   JComboBox combo = new JComboBox();
   JButton start = new JButton("Start");
   JButton stop = new JButton("Stop");
   JButton clear = new JButton("Clear");
   JTextField time = new JTextField("");
   javax.swing.Timer timer;
   SimpleDateFormat timef = new SimpleDateFormat("HH:mm:ss",Locale.getDefault());
   long startT,stopT;
   Date date=new Date();
   public Timer1() {
      super("Timer");
      timef.setTimeZone(TimeZone.getTimeZone("GMT"));
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent ev) {
            dispose();
            System.exit(0);
      setBounds(10,10,400,200);
      getContentPane().setLayout(null);
      start.setBounds(10,30,100,24);
      start.setBackground(Color.green);
      stop.setBounds(10,60,100,24);
      stop.setBackground(Color.red);
      combo.setBounds(10,90,100,25);
      combo.setBackground(Color.blue);
      clear.setBounds(150,60,100,24);
      clear.setBackground(Color.green);
      combo.addItem("1 Hour");
      combo.addItem("2 Hours");
      combo.addItem("3 Hours ");
      combo.addItem("4 Hours");
      combo.addItem("5 Hours");
      combo.addItem("6 Hours");
       combo.addItem("7 Hours");
      combo.setSelectedIndex(0);
      start.addActionListener(new ActionListener() {
         public void actionPerformed( ActionEvent e ) {
            try {
                 startT=(combo.getSelectedIndex()+1)*60*60*1000;  // change if combo box values changed
            catch (Throwable fe) {
               startT=0;
            startT+=System.currentTimeMillis();
            timer.start();
      stop.addActionListener(new ActionListener() {
         public void actionPerformed( ActionEvent e ) {
            timer.stop();
      clear.addActionListener(new ActionListener() {
         public void actionPerformed( ActionEvent e ) {
            time.setText("");
      time.setBounds(150,30,100,24);
      time.setOpaque(true);
      time.setBackground(Color.pink);
      getContentPane().add(stop);
      getContentPane().add(start);
      getContentPane().add(time);
      getContentPane().add(combo);
      getContentPane().add(clear);
      timer = new javax.swing.Timer(1000, new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            stopT = System.currentTimeMillis();
            time.setText(timef.format(new Date(startT-stopT)));
      setVisible(true);
   public static void main (String[] args) {
      UIManager.put("Label.font" ,new Font("Times New Roman",0,23));
      UIManager.put("Button.font",new Font("Arial",1,21));
      new Timer1();
}

Answer 1

simply the user chooses a time from the combobox say
1 hour
and then hits the start button so the timer begins to
countdown.
my problem here is i want when the countdown timer
reaches 0 hour 0 minute 0 second the frame exit (or
any action)not repeating the default time .
got it?Ah, yes, now I understand. So when the user chooses an interval, 1 hour in this case, you calculate the number of seconds that make up that interval. (Doesn't have to be seconds, depends on the granularity of the choices) Then you count down that many seconds like I described before. Each time the timer ticks, decrement the counter, and also convert the number of second left back into hours, minues, seconds and display that.
So the counter becomes the data model that everything's based on, and you format it for display each tick.
startTimer() {
  int interval = // get the interval selected from the combobox
  int seconds = // convert interval to seconds
  start timer with 1 second period
actionPerformed() {
   seconds--;
   if (seconds == 0) {
      stop timer
      do whatever we were waiting for
   else {
       convert seconds to HH:MM:SS format and display in gui
}