Is it possible to rewrite any applet to aplications ?

Question

I am wondering, is it possible to rewrite any applet to aplications ?
dows everything works ? then ?
look at this applet and please rewrite it to aplication if it works, I have tried but some sound did not work. and lots of other thigs went wrong.
import java.awt.*;
import java.util.*;
import java.applet.*;
public class PongBall
     // Variablen
     private int x_pos;               // x - Position des Balles
     private int y_pos;               // y - Position des Balles
     private int x_speed;          // Geschwindigkeit in x - Richtung
     private int y_speed;          // Geschwindigkeit in y - Richtung
     // Positionen
     private int ball_top;          // Obergrenze des Balles
     private int ball_bottom;     // Untergrenze des Balles
     private int ball_left;          // Linke Grenze des Balles
     private int ball_right;          // Rechte Grenze des Balles
     private int comp_top;          // Oberkante des Computerpaddels
     private int comp_bottom;     // Unterkante des Computerpaddels
     private int comp_right;          // Rechte Seite des Computerpaddels
     // Spielfeld (Radius des Balles mit eingerechnet)
     private static final int right_out = 390;
     private static final int left_out = 10;
     private static final int down_out =290;
     private static final int up_out = 10;
     private static final int radius = 10;               // Ballradius
     public PongBall (int x_pos, int y_pos)
          this.x_pos = x_pos;
          this.y_pos = y_pos;
          x_speed = 3;
          y_speed = 3;
     public void move ()
          x_pos += x_speed;
          y_pos += y_speed;
          isBallOut();
     public void isBallOut ()
          // Ball bewegt sich nach links
          if (x_speed < 0)
               if (x_pos < left_out)
                    // Geschwindigkeit umdrehen
                    x_speed = - x_speed;
          // Ball bewegt sich nach rechts
          else if (x_speed > 0)
               if (x_pos > right_out)
                    // Geschwindigkeit umdrehen
                    x_speed = - x_speed;
          // Ball bewegt sich nach oben
          if (y_speed < 0)
               if (y_pos < up_out)
                    y_speed = - y_speed;
          // Ball bewegt sich nach unten
          else if (y_speed > 0)
               if (y_pos > down_out)
                    y_speed = - y_speed;
     public void testForCollisionComputer (ComputerKI computer)
          // Initialisierung der Ballpositionen
          ball_top = y_pos - radius;
          ball_bottom = y_pos + radius;
          ball_left = x_pos - radius;
          ball_right = x_pos + radius;
          // Initialisierung der momentanen Positionen des Paddels
          comp_top = computer.getYPos();
          comp_bottom = computer.getYPos() + computer.getYSize();
          comp_right = computer.getXPos() + computer.getXSize();
          // Ist die Y - Position des Balles zwischen den Paddelpositionen?
          if ((ball_top >= comp_top - radius) && (ball_bottom <= comp_bottom + radius))
               // Ist Paddel in der N�he?
               if (ball_left <= comp_right)
                    // Normales Bouncen
                    x_speed = - x_speed;
     public int getXSpeed ()
          return x_speed;
     public int getYPos ()
          return y_pos;
     public void paint (Graphics g)
          g.setColor (Color.red);
          g.fillOval (x_pos - radius, y_pos - radius, 2 * radius, 2 * radius);
import java.awt.*;
import java.util.*;
import java.applet.*;
import java.net.*;
public class Main extends Applet implements Runnable
     // Variablen
     // Thread
     Thread thread;
     // Ball
     PongBall ball;
     // Computerpaddel
     ComputerKI computer;
     // Doppelpufferung
     private Image dbImage;
     private Graphics dbg;
     public void init(){
          setBackground (Color.black);
          ball = new PongBall (200,200);
          computer = new ComputerKI (200, ball);
     public void start(){
          thread = new Thread (this);
          thread.start();
     public void stop(){
          thread.stop();
     public void run(){
          // Erniedrigen der ThreadPriority um zeichnen zu erleichtern
          Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
          while (true)
               // Neumalen des Fensters
               repaint();
               ball.move();
               computer.move();
               if (ball.getXSpeed() < 0){
                    ball.testForCollisionComputer(computer);
               try
                    // Stoppen des Threads f�r 10 Millisekunden
                    Thread.sleep (10);
               catch (InterruptedException ex)
                    break;
               // Zur�cksetzen der ThreadPriority auf Maximalwert
               Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
     public void paint(Graphics g){
          ball.paint(g);
          computer.paint (g);
     /** Update - Methode, Realisierung der Doppelpufferung zur Reduzierung des Bildschirmflackerns */
     public void update (Graphics g)
          // Initialisierung des DoubleBuffers
          if (dbImage == null)
               dbImage = createImage (this.getSize().width, this.getSize().height);
               dbg = dbImage.getGraphics ();
          // Bildschirm im Hintergrund l�schen
          dbg.setColor (getBackground ());
          dbg.fillRect (0, 0, this.getSize().width, this.getSize().height);
          // Auf gel�schten Hintergrund Vordergrund zeichnen
          dbg.setColor (getForeground());
          paint (dbg);
          // Nun fertig gezeichnetes Bild Offscreen auf dem richtigen Bildschirm anzeigen
          g.drawImage (dbImage, 0, 0, this);
import java.awt.*;
import java.util.*;
import java.applet.*;
class ComputerKI
     /** Diese Klasse Implementiert die Bewegungen des Computers und zeichnet auch die
     Computerpaddel */
     // Deklaration der Variablen
     private int y_pos;                         // y - Position des Paddels
     private int y_speed;                    // Geschwindigkeit in y - Richtung
     private int real_y_pos;                    // Speichert die wirkliche Paddelposition (Mitte)
     // Konstanten
     private static final int x_pos = 15;     // x - Position des Paddels
     private static final int size_x = 10;     // Gr��e des Paddels in x - Richtung
     private static final int size_y = 50;     // Gr��e des Paddels in y - Richtung
     // Ball
     private static PongBall ball;
     // Construktor
     public ComputerKI (int y_pos, PongBall ball)
          this.y_pos = y_pos;
          y_speed = 4;
          this.ball = ball;
     /** Diese Methode bewegt das Paddel */
     public void move ()
          // Mitte des Paddels
          real_y_pos = y_pos + (size_y / 2);
          // Wenn sich Ball von Paddel wegbewegt, werden die Paddel in die Mitte zur�ckbewegt
          if (ball.getXSpeed() > 0)
               // Paddel oberhalb der Mitte
               if (real_y_pos < 148)
                    y_pos += y_speed;
               // Paddel unterhalb der Mitte
               else if (real_y_pos > 152)
                    y_pos -= y_speed;
          else if (ball.getXSpeed() < 0)
               // Solange Paddel nicht auf H�he des Balles ist wird es bewegt
               if ( real_y_pos != ball.getYPos())
                    // Ball oberhalb von Paddel
                    if (ball.getYPos() < real_y_pos)
                         y_pos -= y_speed;
                    // Ball unterhalb von Paddel
                    else if (ball.getYPos() > real_y_pos)
                         y_pos += y_speed;
     public int getXPos()
          return x_pos;
     public int getYPos()
          return y_pos;
     public int getXSize()
          return size_x;
     public int getYSize()
          return size_y;
     /** Diese Methode zeichnet das Paddel */
     public void paint (Graphics g)
          g.setColor (Color.blue);
          g.fillRect (x_pos, y_pos, size_x, size_y);
}

Answer 1

I tryed .. but couldent make it...
there where not suck thing as MyStub and MyApplet..
I know I sould replace it with something else.. but I
did not know WHAT !!
please help.
MyStub stub = new MyStub();
Applet a = new MyApplet();Ok this will be a bit longer post, but it contains fully functional example, simply copy-paste 200 lines of code to single .java file in your favourite IDE and explore it a bit.
Please take note of that this is only example. It's design have several flaws:
- user interface is tightly coupled wih applet stub/context. in real world application IMHO applet stub/context belong to application model (where 'application' means "MyAppletContainer") whereas JDesktop and JInternalFrame are part of view (from MVC pattern).
- applet lifecycle is implmeneted very carelessly. in this example applet is initialzied and started uppon adding to JDesktop and stoped when JInternalFrame is removed from desktop
- codeBase and documentBase properties of AppletStub are not set. see javadoc pages mentioned few lines below, for more information about this two properties.
- some methods in applet context throws UnsupportedOperationException (e.g. getAudioClip) because they are beyond scope of simple example or not really necessary (e.g. mentioned getAudioClip). Another approach is return null instead or leave empty body for methods with void return type.
Before studying sample code you should take a look on applet stub/context declaration in java api. visit url: http://java.sun.com/j2se/1.5.0/docs/api/java/applet/AppletStub.html and http://java.sun.com/j2se/1.5.0/docs/api/java/applet/AppletContext.html
Because this sample is nothing else than briefly scratched one possible implementation of these two interfaces.
Sample:
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.beans.*;
import java.io.*;
import java.net.URL;
import java.util.*;
import javax.imageio.ImageIO;
import javax.swing.*;
public class Main {
    public static void main(String[] args) throws Exception {
        final MyContext context = new MyContext();
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                context.setVisible(true);
    /** Create sample applet */
    public static Applet createApplet() {
        JApplet applet = new JApplet() {
            public void init() {
                showStatus("Another applet initialized");
        applet.add(new JLabel("I am applet"));
        return applet;               
/** Single applet stub */
class MyStub extends JInternalFrame implements AppletStub {       
    /** Create new applet stub*/
    public MyStub(Applet applet, MyContext context) {
        // Setup applet
        this.applet = applet;
        this.context = context;
        applet.setStub(this);
        add(applet);
    /** Owned applet */
    Applet applet;
    /** Context who own this stub */
    MyContext context;
    /** Applet document base */
    URL documentBase;
    /** Applet code base */
    URL codeBase;   
    /** Applet parameters */
    final Map<String, String> param =
            new HashMap<String, String>();   
    /** ##AppletStub##
     * Applet is active whenever frame
     * is selected for example.
    public boolean isActive() {
        return ((JInternalFrame)this).isSelected();
    /** ##AppletStub## */
    public URL getDocumentBase() {
        return documentBase;
    /** ##AppletStub## */
    public URL getCodeBase() {
        return codeBase;
    /** ##AppletStub## */
    public AppletContext getAppletContext() {
        return context;
    /** ##AppletStub## */
    public void appletResize(int width, int height) {
        // allow resize as needed
        setSize(width,height);
    /**##AppletStub## */
    public String getParameter(String name) {
        return param.get(name);
/** Main application frame and applet context */
class MyContext extends JFrame implements AppletContext {
    /** Named InputStreams */
    private Map<String,InputStream> streams =
            new HashMap<String, InputStream>();
    /** All applet stubs */
    private Map<String, MyStub> applets =
            new HashMap<String, MyStub>();
    /** Applets as enumeration */
    private Vector<Applet> appletsEnum =
            new Vector<Applet>();
    /** Ui applet container */
    private JDesktopPane jAppletPane =
            new JDesktopPane();
    /** Status line */
    private JLabel jAppletStatus =
            new JLabel("Add first applet");
    /** Create context */
    public MyContext() throws PropertyVetoException {
        // Create ui
        setSize(600,400);
        setDefaultCloseOperation(EXIT_ON_CLOSE);       
        setLayout(new BorderLayout());
        add(jAppletPane, BorderLayout.CENTER);
        add(jAppletStatus, BorderLayout.SOUTH);
        add(new JButton(new AbstractAction("Add applet") {
            public void actionPerformed(ActionEvent e) {
                doAddApplet();
        }), BorderLayout.NORTH);
        // Very simple applet lifecycle implementation
        // Applet is initialized and started when added and
        // stopped and destroyed when removed from content pane
        jAppletPane.addContainerListener( new ContainerListener() {
            public void componentAdded(ContainerEvent e) {
                Component c = e.getChild();
                if (!(c instanceof MyStub))
                    return ;
                Applet applet = ((MyStub)c).applet;
                applet.init();
                applet.start();
            public void componentRemoved(ContainerEvent e) {
                Component c = e.getChild();
                if (!(c instanceof MyStub))
                    return ;
                Applet applet = ((MyStub)c).applet;
                applet.stop();
                applet.destroy();
    /** Add applet action body */
    private void doAddApplet() {
        // Create some arbitrary applet and name
        Applet applet = Main.createApplet();
        String appletName = "Applet "+System.currentTimeMillis();
        // Add applet and its stub to this container
        MyStub stub = new MyStub(applet, this);
        applets.put(appletName, stub);
        appletsEnum.add(applet);
        // Add to ui
        jAppletPane.add(stub);
        stub.setSize(400,300);
        stub.setVisible(true);
    /** ##AppletContext## */
    public Iterator<String> getStreamKeys() {
        return streams.keySet().iterator();
    /** ##AppletContext## */
    public void setStream(String key, InputStream stream)
    throws IOException {
        streams.put(key, stream);
    /** ##AppletContext## */
    public InputStream getStream(String key) {
        return streams.get(key);
    /** ##AppletContext## */
    public Enumeration<Applet> getApplets() {
        return appletsEnum.elements();
    /** ##AppletContext## */
    public Applet getApplet(String name) {
        MyStub stub = applets.get(name);       
        return stub == null? null: stub.applet;
    /** ##AppletContext## */
    public Image getImage(URL url) {
        try {
            return ImageIO.read(url);
        } catch (IOException ex) {
            JOptionPane.showMessageDialog(this,
                    "IOException: "+ex.getMessage());
            return null;
    /** ##AppletContext## */
    public AudioClip getAudioClip(URL url) {
        throw new UnsupportedOperationException();
    /** ##AppletContext## */
    public void showStatus(String status) {
        jAppletStatus.setText(status);
    /** ##AppletContext## */
    public void showDocument(URL url, String target) {
        throw new UnsupportedOperationException();
    /** ##AppletContext## */
    public void showDocument(URL url) {
        showDocument(url, null);
}Hope this will help a bit.
~~
Adam
Message was edited by:
a3cchan
When I've modified Main.createApplet() to create Your Pong applet I was able to create and run your applet in my simple container with just little glitches (mostly related to my simplistic implementation of ui).
If you wish to 'convert' applet to swing application, You don't have use JDesktop. Add single applet to the frame instead. It should be quite simple from given example.