Applet-demo

import java.applet.Applet;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class Applet_demo extends Applet implements ActionListener, Runnable {

    int n = 20;
    Label label = new Label("20");
    Button button = new Button("reset");

    public void init() {
        setBackground( Color.GREEN);
        add(label);
        add(button);
        button.addActionListener(this);
    }

    public void actionPerformed(ActionEvent e) {
        n = 20;
    }

    public void start() {
        Thread t = new Thread(this);
        t.start();
    }

    public void run() {
        while (n > 0) {
            n--;
            try { Thread.sleep(500); } catch (Exception e) { }
            label.setText(n + "");
        }
        setBackground(Color.RED);
        removeAll();
        add( new Label("Kaboom!"));
        validate();
    }
}