Graphics and JVMs

  To: comp.lang.java.gui
I have written this small test code to show the difference in the
graphical output of 2 different JVMs i.e. Apple JDK 1.5.0 and Windows
JDK 1.5.0_13. When I execute this code in Apple JVM, I can see the
message "Hi There" quite clearly. Whereas, in Windows JVM, the message
is harder be seen if I set Thread.sleep to 100. If I increase the
sleep period, I could see a blinking "Hi There" message. Is this has
to do with the way I have written the code (probably, I am missing
something here) or the JVMs implementation? Either way, how can make
this work the way I wanted it? Please advise. Thanks.

[CODE]
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.util.Random;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;

    public class TestRandomBoxes extends JFrame {
        private Random pointRandomizer = new Random();

        public TestRandomBoxes() {

            final JPanel p = new JPanel() {
                @Override
                public void paint(Graphics g) {
                    g.setColor(getBackground());
                    g.fillRect(0, 0, 200, 200);
                    g.setColor(Color.BLACK);
                    g.fillRect(50 + randomPoint().x, 50 +
randomPoint().y, 50, 50);

                    drawMessage(getParent(), "Hi There");
                }
            };
            p.setPreferredSize(new Dimension(200, 200));

            Thread animator = new Thread() {
                @Override
                public void run() {
                    while (true) {
                        p.repaint();
                        try {
                            Thread.sleep(100); // reduce to increase
update speed
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                }
            };
            animator.start();

            getContentPane().add(new JScrollPane(p));
        }

        private void drawMessage(Container c, String message) {
            if (message.length() < 1) {
                return;
            }

            Graphics g = c.getGraphics();
            int w = g.getFontMetrics().stringWidth(message) + 10;
            int h = g.getFontMetrics().getHeight() + 4;

            g.setColor(new Color(0x33, 0xFF, 0xFF, 50));
            g.fillRect(5, 5, w, h);
            g.setColor(new Color(0x33, 0xFF, 0xFF));
            g.drawRect(5, 5, w, h);
            g.setColor(Color.BLACK);
            g.drawString(message, 8, (5 + h - 4));
        }

        private Point randomPoint() {
            return new Point(pointRandomizer.nextInt(50),
                pointRandomizer.nextInt(50));
        }

        public static void main(String[] args) {
            TestRandomBoxes sl = new TestRandomBoxes();
            sl.setVisible(true);
            sl.pack();
            sl.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            sl.setBounds(600,450, 100, 100);
        }
}
[/CODE]

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