the problem was reported on forum:

http://forum.java.sun.com/thread.jspa?threadID=5120823&tstart=0

Here is the test to reproduce the problem:

import java.awt.*;
import javax.swing.*;

public class JFrameLeak {

    static final long FREQUENCY = 20 * 1000;

    public static void main(String[] arg) {
        
        JFrame f = new JFrame();
        long counter = 0;
        f.setSize(new Dimension(100,100));
        f.show();
        while(true) {
            try {
                new Robot().mouseMove(100,100);
                counter += 1;
                if (counter % FREQUENCY == 0) {
                    System.out.println("Iteration: " + Long.toString(counter));
                }
            } catch (java.awt.AWTException awte) {
                System.err.println("Caught: " + awte.toString());
            }
        }
    }
}