Question

I am confused a bit about wait and notify/notifyAll.

I know there is a lock for every java object. I know wait will release the lock for other thread. How about notify/notifyall? Does notify/notifyAll release the lock it is holding for other thread?

Answer 1

No — notify/notifyAll don’t release locks like wait does. The awakened thread can’t run until the code which called notify releases its lock.

This is what the Javadoc says:

The thread releases ownership of this monitor and waits until another thread notifies threads waiting on this object’s monitor to wake up either through a call to the notify method or the notifyAll method. The thread then waits until it can re-obtain ownership of the monitor and resumes execution.