单独的线程可以继续在另一个对象同步的对象上执行吗？

Question

Say I have an object A which has 2 methods:

public doSomething()
{....}

public synchronised doSomethingElse()
{ ... }

and I have thread1.doSomethingElse() , will it still be possible for thread2.doSomething() to execute or is it blocked by thread1's lock?

If so, how can I make thread1 execute at the same time?

Answer 1

There are two types of synchronization 1. Object level 2. Class level (Class level synchronization is for the static methods only.)

In your case since your methods are not static it is object level synchronization. For object level synchronization you can either synchronize your whole methods or you can synchronize some block of your methods.

When you synchronized one method. Its mean that same object of your class cant access your synchronized method from different threads. As each object have only one lock. If you had called doSomethingElse() for same obj but from different threads. Then It will be accessible by one thread.

Now comes to your answer: As your first method is not synchronized ie something(). It will not be effected in any case if you call it for any no of threads or even call it when your first thread is currently in the method. Locks are only for synchronized methods

Yourclass obj = new Yourclass();
Thread A = new MyThread(obj);
Thread B =  new MyThread(obj);

......

public void run()
{
  \\do what ever you want
   \\both of your methods will be called.
   \\ call them both here.
}

here i have made objects of same Mythread class you can do as per you want. you can make objects of two different implemented thread classes and write your run. In any case it will have no effect on the call.

Answer 2

由于线程2不会尝试获取任何锁，因此它不会被阻塞并且可以与线程1并发运行。您无需执行任何特殊操作。