JInternalFrame não coleta memória

Programação Java
#1

Veja o código:

import javax.swing.ImageIcon;
import javax.swing.JDesktopPane;
import javax.swing.JFrame;
import javax.swing.JInternalFrame;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;


/**
 *
 * @author  Giovanni
 */
public class Desktop extends javax.swing.JFrame {

	private static final long serialVersionUID = 1L;
	
	private JDesktopPane desktopPane;
	
	public Desktop() throws Exception {
		initComponents();
	}

	private void initComponents() throws Exception {
		desktopPane = new JDesktopPane();
		setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
		getContentPane().add(desktopPane, java.awt.BorderLayout.CENTER);
	}

	public JDesktopPane getDesktopPane() {
		return desktopPane;
	}

	public JInternalFrame openModule(final Class frameClass, final String name, final ImageIcon icon) throws Exception {
		for (int i = 0; i < 50; i++) {

			final int cont = i;
			JInternalFrame frame = new JInternalFrame(){
				int[] i = new int[1000000];
				@Override
				protected void finalize() throws Throwable {
					System.err.println("finalize-"+cont);
					super.finalize();
				}
			};
//			JInternalFrame frame = (JInternalFrame) frameClass.newInstance();
			frame.setSize(800,500);
			frame.setTitle(name);
//			frame.setFrameIcon(icon);
//			Dimension desktopSize = desktopPane.getSize();
//			Dimension frameSize = frame.getSize();
//			Point location = new Point(
//			(desktopSize.width - frameSize.width)/2,
//			(desktopSize.height - frameSize.height)/2 );
//			location.x = Math.max(0, location.x);
//			location.y = Math.max(0, location.y);
//			frame.setLocation(location);
//[b]linha 57:[/b]		desktopPane.add(frame);
			frame.setVisible(true);

			Thread.sleep(10);
//			desktopPane.remove(frame);
			frame.doDefaultCloseAction();
			frame = null;
			System.gc();
		}

//		return frame;
		return null;
	}

	public static void main(String[] args) {
		try {
			final Desktop desktop = new Desktop();
			desktop.setSize(800,600);
			desktop.setVisible(true);
			SwingUtilities.invokeLater(new Runnable(){
				public void run() {
					try {
						desktop.openModule(null, "", null);
					} catch (Exception e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				}
			});
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

O código acima coleta normalmente a memoria, mas se descomentar a linha 57 (desktopPane.add(frame);), a coleta para de funcionar, alguem sabe porque.

Java SE 6
Windows XP SP2

no Java SE 5 tambem dá o problema.

#2