difference between the methods sleep() and wait()

Question

Hi Friends What's the difference between the methods sleep() and wait() ?

Vinitha T · Answer

sleep() - Used to pause the process for few seconds or specific time. used to introduce pause on execution, generally. It will keep lock and sleep Used for time-synchronization Will wakeup, until at least time expire or calling interrupt(). synchronized(LOCK){ Thread.sleep(1000); } wait() - T hread goes in waiting state and it won’t call back automatically. Used for inter-thread communication It releases the lock and wait. Used for multi-thread-synchronization. Will wakeup by calling notify(), notifyAll() from object synchronized(LOCK){ LOCK.wait(); }

Rajeesh Menoth · Answer

Hi, sleep It causes current executing thread to sleep for specific amount of time. Its accuracy depends on system timers and schedulers. It keeps the monitors it has acquired, so if it is called from synchronized context, no other thread can enter that block or method. If we call interrupt() method , it will wake up the sleeping thread. wait It causes current thread to wait until either another thread invokes the notify() method or the notifyAll() method for this object It must be called from synchronized context i.e. from block or method.It means before wait() method is called,current thread must have lock on that object. It releases lock on the object on which it is called and added to wait list, so another thread can acquire lock on the object. More details : http://www.java2blog.com/2014/07/difference-between-sleep-and-wait-in.html

Amit Prabhu · Answer

Thread.sleep() sends the current thread into the "Not Runnable" state for some amount of time. The thread keeps the monitors it has aquired -- i.e. if the thread is currently in a synchronized block or method no other thread can enter this block or method. If another thread calls t.interrupt() it will wake up the sleeping thread. object.wait() sends the current thread into the "Not Runnable" state, like sleep(), but with a twist. Wait is called on a object, not a thread; we call this object the "lock object." Before lock.wait() is called, the current thread must synchronize on the lock object; wait() then releases this lock, and adds the thread to the "wait list" associated with the lock. Later, another thread can synchronize on the same lock object and call lock.notify(). This wakes up the original, waiting thread. Basically, wait()/notify() is like sleep()/interrupt(), only the active thread does not need a direct pointer to the sleeping thread, but only to the shared lock object.

Satyapriya Nayak · Answer

http://geekexplains.blogspot.in/2008/05/difference-between-sleep-and-wait.html

Vulpes · Answer

As it's not a straightforward answer, I'd read this article which (for good measure) also deals with 'yield': http://javarevisited.blogspot.co.uk/2011/12/difference-between-wait-sleep-yield.html

difference between the methods sleep() and wait()

Answers (5)