This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
Because yield is a static method in class Thread, myt.yield will not cause the myt thread to yield. It will be the main thread that yields. This is yet another example that proves that static methods should be called through the class, as in Thread.yield(), and not via object references. It's also a case for visiting the API if you have any doubts.