What is the Difference between wait() and sleep()

Question

What is the Difference between wait() and sleep()

What is the difference between a wait() and sleep() in Threads?

Is my understanding that a wait()-ing Thread is still in running mode and uses CPU cycles but a sleep()-ing does not consume any CPU cycles correct?

Why do we have both wait() and sleep(): how does their implementation vary at a lower level?

multithreading java

4 years ago by akshay1995

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**RoliMishra** · Answer 1 · 2021-05-11T13:56:55

A wait can be "woken up" by another thread calling notify on the monitor which is being waited on whereas a sleep cannot. Also, a wait (and notify) must happen in a block synchronized on the monitor object whereas sleep does not:

Object mon = ...;

synchronized (mon) {

    mon.wait();

}

At this point, the currently executing thread waits and releases the monitor. Another thread may do

synchronized (mon) { mon.notify(); }

**kshitijrana14** · Answer 2 · 2021-05-13T13:54:57

One key difference not yet mentioned is that while sleeping a Thread does not release the locks it holds, while waiting releases the lock on the object that wait() is called on.

synchronized(LOCK) {

    Thread.sleep(1000); // LOCK is held

}

synchronized(LOCK) {

    LOCK.wait(); // LOCK is not held

}

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What is the Difference between wait() and sleep()

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