How does Java use the yield() function of the Thread class to give up CPU resources and enter a waiting state?

How does Java use the yield() function of the Thread class to give up CPU resources and enter the waiting state

In Java multi-thread programming, the Thread class is one of the important basic classes. It provides the yield() function that puts the thread into a waiting state, which can give up CPU resources for other threads to execute. This article will introduce how to use the yield() function of the Thread class.

1. The role of the yield() function
The yield() function of the Thread class is used to let the currently executing thread give up CPU resources so that other threads with the same priority have the opportunity to execute. If there are no other threads with the same priority, the yield() function will have no effect.

2. How to use the yield() function
The yield() function of the Thread class is relatively simple to use, just call it. The following is a simple sample code:

public class YieldExample implements Runnable {
    
    public void run() {
        for (int i = 0; i < 5; i++) {
            System.out.println(Thread.currentThread().getName() + " running: " + i);
            Thread.yield();
        }
    }
    
    public static void main(String[] args) {
        Thread thread1 = new Thread(new YieldExample(), "Thread 1");
        Thread thread2 = new Thread(new YieldExample(), "Thread 2");
        
        thread1.start();
        thread2.start();
    }
}

In the above code, we created a class named YieldExample that implements the Runnable interface. The run() method uses a for loop to output the name and number of runs of the current thread. In each loop, the yield() function of the Thread class is called to give up CPU resources. Two threads are created and started in the main() method.

3. Effects and precautions of the yield() function
When we run the above code, we may find that the two threads do not necessarily execute alternately. Because the yield() function only gives other threads a chance to execute, there is no 100% guarantee that other threads will be executed. Factors such as CPU scheduling strategy and thread priority will affect the interruption effect of the yield() function.

In addition, it should be noted that although the yield() function will give up CPU resources, the thread will not enter the waiting state, but will enter the ready state, and may still be selected by the scheduler to continue execution. The yield() function will only take effect if there are no other threads with the same priority.

Summary:
This article introduces how to use the yield() function of the Thread class to yield CPU resources and enter a waiting state. By calling the yield() function, the current thread gives other threads with the same priority a chance to execute. It should be noted that the effect of the yield() function is not 100% predictable, and factors such as scheduling strategy and thread priority will affect its effect. In practical applications, we can reasonably use the yield() function according to specific needs to optimize thread scheduling and resource utilization.

The above is the detailed content of How does Java use the yield() function of the Thread class to give up CPU resources and enter a waiting state?. For more information, please follow other related articles on the PHP Chinese website!