why Object class have notify,notifyall,wait methods

[tirupati d]

Object class have notify, notifyall,wait methods.

But we never use these methods in other class pakages

but we use these methods only in Thread classes.
Java api gave these methods in Object class. Why dont they keep these methods in Thread class...

[plsHelpMe]

Thread communicates by using objects without referencing communicating threads. If these methods are moves to Thread class then each needs a reference to other thread to communicate with it.