Can I execute a thread JPanel?

Question

I want my Jpanel to do a bouncing ball. So I decided to use a thread to update the coordinates regularly. How do I set the panel to visible and at the same time run run()? As you will see, it doesn't work (Code for drawing I haven't placed yet. Instead I placed System.out.println("hello"); to see if it runs):
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.concurrent.Executors;
import java.util.concurrent.ExecutorService;
public class bouncingBall extends JPanel implements Runnable
     private int balls;
     private int ballCount;
     public bouncingBall()
          setSize(500,500);
          addMouseListener(
               new MouseAdapter()
                    public void mouseClicked(MouseEvent e)
                    public void mousePressed(MouseEvent e)
                    public void mouseReleased(MouseEvent e)
          ExecutorService threadExecutor = Executors.newFixedThreadPool( 1 );
          threadExecutor.execute( Thread.currentThread() );
     public void run()
          while(true)
               System.out.println("Hello");     
     public void paintComponent(Graphics g)
     public static void main(String args[])
          JFrame cage = new JFrame("Bouncing Balls");
          bouncingBall app = new bouncingBall();
          cage.setSize(app.getSize());
          cage.add(app);
          cage.setVisible(true);
     }

Answer 1

A JPanel already runs within its own thread... kind
of.
Swing usually works with two threads: one that wraps
up all the displaying objects (this is the one you
create) and another one (which you have no access
to), which takes care of all the event handling and
rendering.
(Ironically, I said this way to often in the last few
days:) Avoid multithreading in Swing/AWT! If you need
anything time based, use the swing timer. If you
still need other threads, make sure that they don't
contain any Swing/AWT components, but just update any
status.
DON'T !! try to split up your displaying items onto
several threads! This might cause unpredictable
lockdowns!What about this new paradigm I'm reading about in the latest Swing books that says there is a flaw in the traditional way of creating a JFrame, e.g.
JFrame aWindow = new JFrame("title");
aWindow.setVisible(true);that makes them not thread safe? The new model for creating JFrames says you need to add them to the event queue. That seems to belie your statement that we don't have access to the "other thread' that handles events.
Actually, below is a Hello World example of the new method for creating a JFrame that I found in the java docs(ugly!). It involves two steps:
1) Create the JFrame inside a method
2) Attach the method to the event dispatching thread
import javax.swing.*;       
public class HelloWorldSwing {
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
    private static void createAndShowGUI() {
        //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);
        //Create and set up the window.
        JFrame frame = new JFrame("HelloWorldSwing");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        //Add the ubiquitous "Hello World" label.
        JLabel label = new JLabel("Hello World");
        frame.getContentPane().add(label);
        //Display the window.
        frame.pack();
        frame.setVisible(true);
    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
}http://java.sun.com/docs/books/tutorial/uiswing/learn/example1.html
If you still need other threads, make sure that
they don't contain any Swing/AWT components,
but just update any status.Can you pass a Swing Component reference to the thread's constructor and call repaint() from inside the thread?