As wait() notify() and notyfyAll() methods are present in Object class which is a super class for all the classes. There is no need to redefine the same methods in other classes as they all will inherit them from there super class Object.

wait() notify() and notyfyAll() methods these are inherited from Object class.
if you call wait() method it will enter in to the monitor for specfic time or ideal time when call notify() it will enter from the waiting pool to ready state
When notifyAll() calls then it will bring all of the waiting threads from waiting pool to ready state

Each object in java is associated with a lock and the wait and notify methods are not associated with a thread but with a lock so coupling locks and objects meant that each object should have wait and notify methods that operate on that object s lock.

Java provides a way to lock the code for a thread which is currently executing it using the synchorinized keyword and making other threads that wish to use it wait until the first thread is finished.These other threads are placed in the waiting state .Once the first thread completes it task than it notifies others in the queue by giving the lock to JVM.Now JVM decides which thread will exceute next by its internal algo.Hence the wait and notify methods has to be in Object class as it acquires lock and has to notify others.....