Question

class A {
    private synchronized f() {
        ...
        ...
    }

    private void g() {
        ...
        ...
    }
}

If thread T1 is running f() which is synchronized, can thread t2 run g() which is not synchronized at the same point of time, while T1 is still running f()?

Answer 1

Not on the same instance of A. The instance itself is the lock so two execute the two methods at the same time with two threads you would need two instances of A.