In-depth analysis of Java's underlying technology: How to implement thread scheduling and lock optimization
Introduction:
In Java development, it involves the concurrent execution of threads and shared resources Access, thread scheduling and lock optimization are essential core technologies. This article will analyze how to implement thread scheduling and lock optimization in Java from a low-level perspective, and give specific code examples.
1. Thread Scheduling
The priority of a thread in Java is controlled by the setPriority() and getPriority() methods provided by the Thread class. The priority of threads is divided into levels 1~10, with level 1 being the lowest priority and level 10 being the highest priority. You can set the thread's priority through setPriority(), and getPriority() is used to get the thread's priority.
The JVM will allocate CPU time according to the priority of the thread, but there is no guarantee that a thread with a high priority will execute faster than a thread with a low priority. Because the specific scheduling situation is also affected by the operating system.
public class ThreadPriorityExample { public static void main(String[] args) { Thread t1 = new MyThread(); Thread t2 = new MyThread(); t1.setPriority(Thread.MIN_PRIORITY); t2.setPriority(Thread.MAX_PRIORITY); t1.start(); t2.start(); } static class MyThread extends Thread { @Override public void run() { System.out.println("线程优先级:" + getPriority()); } } }
In the above example, we create Two threads are named t1 and t2, and different priorities are set respectively. Then after starting the thread, obtain the priority of the thread through the getPriority() method and output it.
2. Lock optimization
public class LockOptimizationExample { private static int count = 0; private static final Object lock = new Object(); public static void main(String[] args) { for (int i = 0; i < 10; i++) { new Thread(() -> { synchronized (lock) { count++; System.out.println("当前值:" + count); } }).start(); } } }
In the above example, we use the synchronized keyword to increase count Lock ensures the atomic operation of count in a multi-threaded environment. By locking with the synchronized keyword, we can avoid the problem of data inconsistency caused by multiple threads modifying count at the same time.
Conclusion:
This article introduces the related concepts of thread scheduling and lock optimization in Java, as well as specific code examples. Thread scheduling and lock optimization are indispensable core technologies in Java development. Understanding and mastering these technologies is very important to improve program concurrency performance and ensure data consistency. I hope this article will be helpful to readers in the underlying Java technology.
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