Question about synchronized re-entry

Question

Suppose I have the following code:
* method performs actions that require synchronization on state but
* the programmer ensures manually that it is only called in a context
* where we are already synchronized on state
private void veryPrivateMethod() {
    //synchronized(state) { (*) required?
    if (state == 999) {
        // perform actions that require synchronization on state
public void anotherMethod() {
    synchronized(state) {
        if (state == 42)
            state = 43;
        veryPrivateMethod();
}See (*): If I ensure manually that veryPrivateMethod will only be called in a context where we are already synchronized on state, do I still need to specifically synchronize on state in the method (reentrant synchronization), or will it be better performance-wise and still safely synchronized if I omit the synchronized statement in veryPrivateMethod()?
Thanks!

Answer 1

gimbal2 wrote:
932196 wrote:
I synchronize on it whenever I change / compare-change it. Is this a bad ideaThat's a maybe. Its not a bad idea, as long as you realize that doing this has no special meaning and will offer no special protection. You can synchronize on just about any object you want, as long as other threads synchronize on the exact same object when wanting to execute the same section(s) of volatile code.the comment in the example is:
// perform actions that require synchronization on statethis leads me to believe that the code is not correctly synchronized currently. like i said, changing the reference to the object you are synchronizing on pretty much always leads to broken code.