Thread.sleep(1000);
Thread.sleep(50);
  public static void main(String args[])  {    try    {      long start = System.currentTimeMillis();      System.out.println("sleeping");      Thread.sleep(1000);      long end = System.currentTimeMillis();      if ((end - start) > 1100 || (end - start) < 990)        System.out.println ("failed");      else	System.out.println("ok");    }    catch (InterruptedException x)    {      System.out.println("error: Thread interrupted.");    }  }