Difference between wait() and sleep()

Question

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

Is my understanding that a wait()-ing Thread is still in runni

Answer 1

The methods are used for different things.

Thread.sleep(5000);   // Wait until the time has passed.

Object.wait();        // Wait until some other thread tells me to wake up.

Thread.sleep(n) can be interrupted, but Object.wait() must be notified. It's possible to specify the maximum time to wait: Object.wait(5000) so it would be possible to use wait to, er, sleep but then you have to bother with locks.

Neither of the methods uses the cpu while sleeping/waiting.

The methods are implemented using native code, using similar constructs but not in the same way.

Look for yourself: Is the source code of native methods available? The file /src/share/vm/prims/jvm.cpp is the starting point...