CountDownSwing.java

package ui;

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;

public class CountdownFrame extends JFrame {

    private JLabel label;

    public CountdownFrame() {
        label = new JLabel();
        add(label);
        JButton button = new JButton("Click me, now!");
        button.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                (new Thread(new CountDown())).start();
            }
        });
        add(button, BorderLayout.SOUTH);

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(160, 160);
        setVisible(true);
    }

    class CountDown implements Runnable {

        public void run() {
            int hours = 0, minutes = 1, seconds = 5;
            boolean kt=true;
            while (kt) {
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException x) {
                }
                seconds -= 1;
                if (seconds == -1) {
                    minutes -= 1;
                    seconds = 59;
                }
                if (minutes == -1) {
                    minutes = 59;
                    hours -= 1;
                }
                String h = hours<10 ? "0"+hours : ""+hours;
                String m = minutes<10 ? "0"+minutes : ""+minutes;
                String s = seconds<10 ? "0"+seconds : ""+seconds;

                label.setText(h+":"+m+":"+s);
                if(hours==0 && minutes==0 && seconds==0){
                    JOptionPane.showMessageDialog(null, "Hết con mẹ nó giờ rồi");
                    kt = false;
                }
            }

        }
    }

    public static void main(String[] args) {
        CountdownFrame frame = new CountdownFrame();
    }
}