yield() vs join() vs sleep()

This is another popular core interview question. Look at the following table.

yield() vs sleep()

• Both methods are used to stop execution of current thread.
• But the different is, yield() method release its lock of object while sleep() method doesn't release its lock of object. 

wait() vs sleep()

• sleep() method allows to thread to go to sleep state for given time. As you know, it doesn't release the lock of object.
• wait() allows thread to release the lock and goes to blocked state. It can be active only by calling notify() or notifyAll() methods.

notify() vs notifyAll()

• notify() method activate the first thread which called wait().
• notifyAll() method activate all threads which called wait(), highest priority thread will run first.