Run the following program under the profiler and turn on memory profiling. You 
will see that the finalize methods never get called, and the profiling data 
shows the Main thread objects are never garbage collected. Run the program as 
normal (without the profiler) and you will see that the finalize methods do 
get called. This is very misleading when you are trying to find memory leaks 
using the profiler.

See also http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6520834

/*
 * Main.java
 *
 * Created on February 8, 2007, 10:31 AM
 */

package Threads;

/**
 *
 * @author ekolotyluk
 */
public class Main extends Thread
{ 
    public void run()
    {
        System.out.println(getName() + " - starting");
        try
        {
            sleep((int) (Math.random() * 100000));
        }
        catch (InterruptedException e)
        {

        }
        System.out.println(getName() + " -         stopping");
    }

    public void finalize()
    {
        System.out.println(getName() + " -                  finalizing");
    }

    public static void main(String [] arguments)
    {
        for (int i = 0; i < 100; i++)
        {
            Main main = new Main();
            main.start();
            try
            {
                Thread.sleep(2000);
                System.gc();
            }
            catch (InterruptedException e)
            {

            }
        }

        System.exit(0);
    }
}