Java: A synchronized method in the superclass acquires the same lock as one in the subclass, right?

Question

class A {
    public synchronized void myOneMethod() {
        // ...
    }
}

class B extends A {
    public synchronized void myOtherMethod() {
        // ...
    }
}
         


        

Answer 1

Yes. Java uses "monitors" to implement synchronization, and synchronized methods use the object instance they're called on as monitor, which is obviously the same in this case.

Note that this is NOT true for static methods! There, the class instance of (I think) the declaring class is used, which would not be the same one.