在类非静态属性上应用同步

Question

public class main class { public static void main(String[]args){

    T1 ok = new T1();
    T2 ok1 = new T2();
    ok.start();
    ok1.start();
}

}

public class T1 extends Thread {

@Override
public void run() {
    DemoClass q = new DemoClass();
    for (int i = 0; i <= 5; i++)
        try {
            q.demoMethod();
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
}

}

public class T2 extends Thread {

@Override
public void run() {
    DemoClass q = new DemoClass();
    for (int i = 0; i <= 5; i++)
        try {
            q.demoMethod1();
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
}

}

public class DemoClass {
String s = "";
String s1 = "";
public void demoMethod() throws InterruptedException {
    System.out.println(Thread.currentThread().getName() + " Entered m1");

    synchronized (s) {
        System.out.println(Thread.currentThread().getName() + " Inside m1 ");

        Thread.sleep(5000);
    }
    System.out.println(Thread.currentThread().getName()+" m1");

}

public void demoMethod1() throws InterruptedException {
    System.out.println(Thread.currentThread().getName() + " Entered m2");


        System.out.println(Thread.currentThread().getName() + " Inside m2 ");

        Thread.sleep(5000);
    
    System.out.println(Thread.currentThread().getName()+" m2");

}

}

即使我创建了DemoClass的单独对象，然后通过单独的线程调用单独的方法。为什么一次只有一个线程工作？

或者，如果有人可以建议我们将调用 DemoClass 中的代码的锁定类型

Answer 1

您正在< code>s上同步，它始终是同一个对象。

不要那样做。如果要同步任何内容，请在< code>this上同步。