Need help with window drawing thing

Question

Hi all,
This program moves a circle around a screen. It used to work, even in the full screen mode that I have made it in. However, the contents of windowClass that set the attributes of the window (size, full screen, etc) used to be in the run() method of the main class. When I moved them to the windowClass class to tidy up the code, the program for some reason no longer paints the contents of the 'artwork' object to the screen. The KeyEvents still work, and everything. I can't figure out why, because this change was the only one I made between the program working and not working - I have not changed anything relating to the container or artwork at all.
In case you have not figured out yet this is an application, not an applet.
Sorry about the lack of programming notes, this program was just intended as a quick test and while I was writing it I did not see the need. (from the name you can see it started off as a test of KeyEvents but went a little further) If nobody can follow then I will put them in, but I would rather not because that takes time.
Thank you!
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class TryEvents extends Thread implements KeyListener
    boolean left = false;
    boolean right = false;
    boolean up = false;
    boolean down = false;
    static Toolkit theKit = Toolkit.getDefaultToolkit();
    static Dimension screenSize = theKit.getScreenSize();
    public static int xWin = screenSize.width;
    public static int yWin = screenSize.height;
    private static TryEvents theApp;
    private static JFrame window;
    private static theArtwork artwork;
    private static Container content;
    private static GraphicsEnvironment environment =
        GraphicsEnvironment.getLocalGraphicsEnvironment();
    private static GraphicsDevice device = environment.getDefaultScreenDevice();
    public static void main(String[] args)
        Thread theApp = new TryEvents();
        theApp.start();
    public void run()
        window = new windowClass("Trying Events", device);
        content = window.getContentPane();
        artwork = new theArtwork();
        content.add(artwork);
        window.addKeyListener(this);
        while(true)
            if(left == true && right == false)
                artwork.moveLeft();
            if(right == true && left == false)
                artwork.moveRight();
            if(up == true && down == false)
                artwork.moveUp();
            if(up == false && down == true)
                artwork.moveDown();
            try
                Thread.sleep(15);
            catch(InterruptedException e) {}
    public void keyPressed(KeyEvent e)
        int key = e.getKeyCode();
        if(key == KeyEvent.VK_LEFT)
            left = true;
        if(key == KeyEvent.VK_RIGHT)
            right = true;
        if(key == KeyEvent.VK_UP)
            up = true;
        if(key == KeyEvent.VK_DOWN)
            down = true;
        if(key == KeyEvent.VK_ESCAPE)
            System.exit(0);
    public void keyReleased(KeyEvent e)
        int key = e.getKeyCode();
        if(key == KeyEvent.VK_LEFT)
            left = false;
        if(key == KeyEvent.VK_RIGHT)
            right = false;
        if(key == KeyEvent.VK_UP)
            up = false;
        if(key == KeyEvent.VK_DOWN)
            down = false;
    public void keyTyped(KeyEvent e) {}
class windowClass extends JFrame
    private static GraphicsDevice device;
    public windowClass(String title, GraphicsDevice device)
        this.device = device;
        setTitle(title);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setUndecorated(true);
        setResizable(false);
        device.setFullScreenWindow(this);
class theArtwork extends JPanel
    int xPoint = 0;
    int yPoint = 0;
    int xcircleSize = 30;
    int ycircleSize = 30;
    int movement = 7;
    public void paintComponent(Graphics g)
        super.paintComponent(g);
        g.setColor(Color.white);
        g.fillRect(0,0,TryEvents.xWin, TryEvents.yWin);
        g.setColor(Color.blue);
        g.fillOval(xPoint, yPoint, xcircleSize, ycircleSize);
    public void update(Graphics g)
        paint(g);
    public boolean canMove()
        boolean canMove = true;
        if(xPoint < 0 | yPoint < 0)
            canMove = false;
        if(xPoint + xcircleSize > TryEvents.xWin)
            canMove = false;
        if(yPoint + ycircleSize > TryEvents.yWin)
            canMove = false;
        return canMove;
    public void moveRight()
        xPoint += movement;
        if(canMove())
            repaint();
        else
            xPoint -= movement;
    public void moveLeft()
        xPoint -= movement;
        if(canMove())
            repaint();
        else
            xPoint += movement;
    public void moveDown()
        yPoint += movement;
        if(canMove())
            repaint();
        else
            yPoint -= movement;
    public void moveUp()
        yPoint -= movement;
        if(canMove())
            repaint();
        else
            yPoint += movement;
}Thank you again!

Answer 1

Okay, just figured out why now, the call to method:
device.setFillScreenWindow(...)
makes the frame visible, so changes to the content pane are not updated automatically, you have to do a content.validate() to make sure that the changes are applied if it is already visible. By resetting the window's content pane content.validate() must be called...
So you could do several things:
1) do the window.setContentPane(content); like I did before,
2) do a content.validate(); after you add drawing to it...
3) move device.setFullScreenWindow(...) from the constructor to run
method after you set up the content pane...