6.33 Thread.sleep

1. When Does a Thread Wake Up After sleep Ends?

Thread.Sleep(1000);

Suppose a thread runs the code above at 2020-01-09 22:47:54. Will it immediately continue executing at 2020-01-09 22:47:55?

• Answer

Not necessarily. The code only means that at 2020-01-09 22:47:55 the thread has an opportunity to compete for the CPU. It does not mean that it has already obtained the CPU and started executing.

2. Thread.sleep vs. Object.wait

	sleep	wait
Usage	Static method of Thread; call it directly	Instance method of Object; used together with synchronized
Purpose	Pauses the current thread for a specified amount of time	Makes the current thread wait
Releases the lock	No	Yes
Gives up the CPU	Yes	Yes
How it wakes up	Wakes automatically when the time expires	Woken by notify

3. References

• Understanding the Thread.Sleep Function - CNBlogs