Wait and notify

There are five methods implemented in the Objectclass that can be used to get further synchronization functionality—wait, with three different timeout argument signatures, notify, and notifyAll. To call wait, the calling thread should have the lock of the Object on which wait is invoked. It means that you can only invoke wait from inside a synchronized block and, when it is called, the thread gets BLOCKED and releases the lock. When another thread calls notifyAll on the same Object, the thread gets into the RUNNABLE state. It cannot continue execution immediately as it cannot get the lock on the object. The lock is held at that moment by the thread that just called notifyAll. However, sometime after the other thread releases the lock, in other words, it gets out of the synchronized block, the waiting thread can acquire it and can continue the execution.

If there are more threads waiting on an object, all of them get out of the BLOCKED state. The notify method wakes only one...