Java has no function level lock?

Question

Hi, everyone!
I am a C++ programmer before and after reading the
internal implemention method of Java Thread. I think
Java has no function level lock and only object level
lock. I mean to acquire a function lock is the same as
acquire an object's lock.
For example, when objectA.synchronizedFunctionA is called,
suppose synchronizedFunctionA is a synchronized function of
class A. Java only check whether objectA is locked. The synchronized
function synchronizedFunctionA has no individual function level
lock.
Am I correct?
If I am correct, I think in some certain application, function level
lock will be more efficient than object level lock. Even though it
should be used more carefully.
Thanks in advance,
George

Answer 1

You could have a custom lock object for every method to get the same functionality.
I.e. instead of...
public synchronized void mySynchMethod() {
}you'd do..
public void mySynchMethod() {
   synchronize(thisMethodLock) {
}where thisMethodLock would be some object used as a lock by only that method.