Repainting inside loop that uses sleep method

[Flo Powers]

Hi, this may not be the right section for this post - may be an issue more suited under the swing section, for example - not sure...

I'm making a simple application that draws shapes on a JFrame (not with applet, but with a class that extends JFrame and has a main method). The paint method runs an endless while loop in which I invoke Thread.sleep(3000) in a try-catch block.

The try block also creates a Polygon with 3 - 8 points (all within the bounds of the window), and paints it with reference to the Graphics object. I then try to invoke repaint for each loop. I have experienced before that I've got that to work with applets, but not with an "application" (by which I mean it has a main method, and doesn't require an appletviewer or a web page in which to run).

It also doesn't unload the process from RAM when I click the close button on the window, even though in the main method I've added a WindowListener. Could that be because of the while loop with the Thread? I.e. it's not listening when I click, because the Thread is sleeping...?

I don't know what's wrong, other than (probably) my overall approach... Any comments? Here's the code so far:

import java.awt.*;
import java.awt.Event;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
 
import javax.swing.*;
 
public class RandomPolygon extends JFrame
{

public RandomPolygon()
{
super("Drawing Polygons");
setSize( 300, 300 );
setVisible(true);
}

public void paint( Graphics g )
{
while( true )
{
Polygon polly = new Polygon();
try
{
for(int i = 0; i < Utils.rnd(5, 3); i++)
polly.addPoint(
Utils.rnd(290,5), 
Utils.rnd(290,5)
);

g.fillPolygon(polly);
Thread.sleep(3000);
polly.reset();
repaint();
}
catch( InterruptedException io)
{
System.exit(0);
}

}
}

public static void main(String[] args) 
{
RandomPolygon app = new RandomPolygon();
app.addWindowListener( 
new WindowAdapter() 
{
public void windowClosing( WindowEvent e)
{
System.exit(0);
}
}
);
}
}

[ March 27, 2006: Message edited by: Flo Powers ]
[ March 27, 2006: Message edited by: Flo Powers ]

[Harish Kashyap]

Your paint method is being invoked recursively