java synchronized 锁住同一个类的静态方法和非静态方法会互斥吗？

快来打我* 2024-03-30 17:11 13阅读 0赞

> 我们知道synchronized关键词加在方法上可以对方法加上锁，让不同线程执行该方法抢占锁来顺序执行，我们知道对静态方法锁定的时候是对该类class对象上加上锁，而非静态方法上锁时会对该实例对象头上锁，那假设我用两个不同线程对静态方法和非静态方法分别调用执行，它们会互斥执行吗？

/**
     * 静态和非静态synchronized锁定方法测试
     * @author humorchen
     * @date 2023/1/10 16:47
     */
    public class StaticAndNotStaticTest {
        
        public static synchronized void staticSay() {
        
            System.out.println("static say begin");
            try {
        
                Thread.sleep(4000);
            } catch (InterruptedException e) {
        
                throw new RuntimeException(e);
            }
            System.out.println("static say end");
        }
    
        public synchronized void notStaticSay() {
        
            System.out.println("not static say begin");
            try {
        
                Thread.sleep(4000);
            } catch (InterruptedException e) {
        
                throw new RuntimeException(e);
            }
            System.out.println("not static say end");
        }
    
        public static void main(String[] args) {
        
            StaticAndNotStaticTest staticAndNotStaticTest = new StaticAndNotStaticTest();
            Thread notStaticThread = new Thread(() -> {
        
                staticAndNotStaticTest.notStaticSay();
            });
    
            Thread staticThread = new Thread(() -> {
        
                StaticAndNotStaticTest.staticSay();
            });
            notStaticThread.start();
            staticThread.start();
            try {
        
                notStaticThread.join();
                staticThread.join();
            } catch (InterruptedException e) {
        
                throw new RuntimeException(e);
            }
        }
    }

![在这里插入图片描述][edcc53908c8c4260bbc43c3393673700.png]  
五秒后

![在这里插入图片描述][d3d2a8086eb24697a737a5ad549b0006.png]  
得出结论，不互斥，原因是它们锁的对象不一样，一个是类，一个是实例对象

[edcc53908c8c4260bbc43c3393673700.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/73296fe07701475599591f0a5c2a4fb7.png
[d3d2a8086eb24697a737a5ad549b0006.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/245ed0977aa94ed29eb658a8ff80a2fe.png