This week's book giveaway is in the OCAJP forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide 1Z0-808 and have Jeanne Boyarsky & Scott Selikoff on-line! See this thread for details.
sleep and yield always act on the currently executing thread. This is the one that is executing a command like this: aThread.yield(); maybe there is a possible confusion because it could be thought that the currently executing thread is aThread. But this is not the case. yield acts on the thread that is executing the above piece of code.