Difference bet wait(milisec) and sleep(milisec)

[Munish Dabra]

They both did the same job.what actually makes them different at back end

[William Brogden]

Well, obviously, a Thread in a wait() can be notify() -ed
whereas a Thread in a sleep() can only be interrupted.
Also, a Thread in a wait() has released its lock on an object, whereas a Thread in a sleep() retains any locks it may have.
Bill

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[Vladimir Kositsky]

From Khalid Mughal book:
"- Waiting state:When in Running state , a thread can call the wait() method defined in Object [ !!! -V.K.] class to put itself unto the Waiting state. It must be notified by another thread, in order to move to the Ready - to- run state .
- Sleeping state: A call to the static method sleep() in the Thead (!!! - V.K.) class couses the current thread in Running state to transit to the Sleeping state. It wakes up after specified amount of time(...)
-Ready - to-run state: (...)In the Ready - to run state , a thread awaits its turn to get CPU time."
Those methods provides absolutely different functionality of threads. Sleep() makes thread to run with intevals, wait()[ and notify()] controls accessibility of synchronized methods of object for competing ( more then one) threads.

[hh33]

After a thread on wait(xx) is notified (or timeout), it must seek lock first and then go to ready state. A thread on sleep(xx) goes to ready state immediately after interruption, or timeout. Wait(xx) is actually wait for an chance to get lock back.

hh