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

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Ashutosh Patel · Answer

Difference between wait() and sleep()

Both wait() and sleep() methods are used in Java for concurrent scheduling, but serve different purposes:

wait()

In synchronization contexts, it is used to suspend the execution of a thread until another thread shows up.
The call must come from a synchronized block or method.
Release the lock of the object being called.

Example-

synchronized (sharedObject) {
   while (!condition) {
       sharedObject.wait(); // Thread waits until condition is met
   }
   // Continue execution after condition is true
}

sleep()

Used to suspend the use of a thread for a specified period of time.
Nothing can release the lock.
It is not tied to synchronization and can be invoked from any context.

Example-

try {
   Thread.sleep(1000); // Pauses execution for 1 second
} catch (InterruptedException e) {
   e.printStackTrace();
}

Specifically, wait() is used for communication between threads in synchronous context, while sleep() is used to pause execution for a specified period of time, regardless of session

Also, Read: What are the key features introduced in Java 8?

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

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Difference between wait() and sleep()