异常的最终去向是哪里？

 public static void main(String[] args)
    {
        for (int i = 0; i < 3; i++)
        {
            final Thread a = new Thread(new Runnable()
            {

                public void run()
                {
                    throw new UnsupportedOperationException("Not supported yet.");
                }
            });
            Thread b = new Thread(new Runnable()
            {

                public void run()
                {
                     a.run();
                }
            });
           b.run();
            try
            {
                Thread.sleep(5000);
            }
            catch (InterruptedException ex)
            {
                Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
            }
        }

 测试了一下，确实中止在main线程