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This article mainly explains "what is the use of Java's Sleep () method". The content of the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "what is the role of Java's Sleep () method"?

Suspends execution of the current thread (that is, the Java thread that called the method) for a period of time, giving other threads a chance to continue execution, but it does not release the object lock. That is, if there is a Synchronized synchronization block, other threads still have different access to shared data. Note that this method catches exceptions.

For example, there are two threads executing at the same time (no Synchronized), one Java thread priority is MAX_PRIORITY, the other is MIN_PRIORITY, if there is no Sleep () method, only the high-priority thread execution is completed, the low-priority thread can execute; but when the high-priority thread sleep (5000), the low-priority thread has a chance to execute.

In short, sleep () can give low-priority Java threads a chance to execute, as well as high-priority threads with the same priority.

Join ()

The join () method causes the thread calling the method to finish execution before then, that is, waiting for the thread calling the method to finish execution before continuing to execute. Note that this method also catches exceptions.

Yield ()

It is similar to sleep (), except that the user cannot specify how long to pause, and the yield () method can only give Java threads of the same priority a chance to execute.

Wait () and notify (), notifyAll ()

These three methods are used to coordinate the access of multiple Java threads to shared data, so they must be used within the Synchronized statement block. As mentioned earlier, the keyword Synchronized is used to protect shared data and prevent other threads from accessing it. But the flow of the program is very inflexible. How can we give other threads a chance to access the shared data before the current thread exits the Synchronized data block? At this point, we use these three methods to control flexibly.

The wait () method pauses execution of the current thread and releases the object lock flag so that other threads can enter the Synchronized data block, and the current thread is placed in the object wait pool. When the notify () method is called, an arbitrary thread is removed from the object's waiting pool and placed in the lock flag waiting pool. Only the Java thread in the lock flag waiting pool can obtain the lock flag; if there are no threads in the lock flag waiting pool, notify () does not work.

NotifyAll () removes all Java threads waiting for that object from the object waiting pool and places it in the lock flag waiting pool.

Thank you for your reading, the above is the content of "what is the role of Java's Sleep () method". After the study of this article, I believe you have a deeper understanding of the role of Java's Sleep () method, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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