在下面的代码,我试图找出线程在synchronized块处理执行:线程执行序列
public class ThreadExp {
public static void main(String[] args) throws InterruptedException {
MyRunnable r = new MyRunnable();
Thread t1 = new Thread(r, "Thread1");
Thread t2 = new Thread(r, "Thread2");
t1.start();
t2.start();
}
}
class MyRunnable implements Runnable {
@Override
public void run() {
callFn();
}
private void callFn() {
System.out.println(Thread.currentThread().getName() + ": entered callSync()");
synchronized (Thread.currentThread()) {
System.out.println(Thread.currentThread().getName() + ": inside sync");
try {
Thread.currentThread().sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName() + " leaving sync");
}
System.out.println(Thread.currentThread().getName() + ": leaving callSync()");
}
}
实际输出:
Thread1: entered callFn()
Thread2: entered callFn()
Thread1: inside sync block
Thread2: inside sync block
// 5000 millisec sleep
Thread2 leaving sync block
Thread1 leaving sync block
Thread2: leaving callFn()
Thread1: leaving callFn()
而我预期的东西如:
Thread1: entered callFn()
Thread2: entered callFn()
Thread1: inside sync block
// 5000 millisec sleep
Thread1 leaving sync block
Thread1: leaving callFn()
Thread2: inside sync block
Thread2 leaving sync block
Thread2: leaving callFn()
总的来说,我认为Thread1会获得锁,然后进入睡眠。只有在线程1完成后,线程2才能进入同步块。
同步线程对象将永远不会阻塞。它怎么可能?多线程尝试输入锁时发生争用,但在您的情况下,每个线程正在输入唯一的锁。 – dlev