Can't get ball to move

Question

I am trying to make a ball move on my applet but am having trouble trying to make it happen. I have a class golfcourse which draws the course, a ball which handles the drawing and (hopefully) it's movements and a bar class which extends JProgressBar and stops moving from left to right when clicked on.
I want to firstly make the ball move forward based on the where the bar is stopped (percentage) and currently have some permanent numbers which will eventually be based on club selected.
What I would like to ask is whether I am on the right track or if not, can you provide any good advice?
Here is my code:
class ball
public class Ball
     int x_pos = 228; // x position
     int y_pos = 445; // y position
     int y_final = 745;
     int x_final = 228;
     int r = 10; //radius
     DistanceBar12 dest;
     int targetDest;
     int maxDist = 200;
     private int distance; // how far the ball will travel after distance bar pressed
     public void paint(Graphics g)
          g.setColor(Color.black);
          g.fillOval(x_pos, y_pos, r, r);
     public void move()
                         y_pos ++;
     } // close move()
          public int getY_pos() 
          return y_pos;
          public int getX_pos() 
          return x_pos;
          public int getmaxDist() 
          return maxDist;
} // close classclass GameScreen2
class GameScreen2 extends JPanel {
     GolfCourse gc = new GolfCourse();
     Ball ball = new Ball();
      public GameScreen2(){
      public void paintComponent(Graphics graphics) {
         Graphics2D g = (Graphics2D) graphics;
         super.paintComponent(g); //paint background
gc.paint(g);
ball.paint(g);
   }class MainGame2
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.Border;
public class MainGame2 extends JApplet implements Runnable{
final DistanceBar12 bar = new DistanceBar12();
int finalDest;
Thread th;
Ball ball;
   public void init() {
      buildUI(getContentPane());
        bar.start();
        bar.setMaximum(100);
            addMouseListener(new MouseAdapter() {
        public void mouseClicked(MouseEvent e) {
                bar.stop();
                JOptionPane.showMessageDialog(bar,
                 bar.getValue() + " percent");
                bar.start();
   void buildUI(Container container) {
      container.setLayout (new BoxLayout (container, BoxLayout.Y_AXIS));
      GameScreen2 screen = new GameScreen2();
      container.add(screen);
       container.add(bar);
      screen.setAlignmentX(LEFT_ALIGNMENT);
      bar.setAlignmentX(LEFT_ALIGNMENT);
   public void start()
          th = new Thread (this);
          th.start ();
     public void stop()
     public void run ()
          finalDest = ball.getY_pos() + (bar.getValue() * ball.getmaxDist() / 100);
          // Erniedrigen der ThreadPriority um zeichnen zu erleichtern
          Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
          while (true)
               if (ball.y_pos < finalDest)
                    ball.move();
                    repaint();
               try
                    // Stoppen des Threads f�r 10 Millisekunden
                    Thread.sleep (15);
               catch (InterruptedException ex)
                    // do nothing
               // Zur�cksetzen der ThreadPriority auf Maximalwert
               Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
// ball and course do not appear in applet when this is included
//          public void paint (Graphics g)
//          ball.paint(g);
     public void destroy()
}

Answer 1

If you move the ball-position-updating code to Ball, you'll have to make it implement Runnable, and you'll need to pass a reference to the component that contains it so you can call its repaint method. Alternatively you can try active rendering (I believe that's the correct term) -- where the applet doesn't wait for repaints() to be called.