I'm not sure if I'm interpreting the javadoc right. When using a ReentrantLock after calling the lock method and successfully gaining a lock, can you just access any object without any synchronized blocks and the happend-before relationship is magically enforced?
I don't see any connection between the ReentrantLock and the objects I'm working on, that's why it is hard to believe I can work on them safely. But this is the case, or am I reading the javadoc wrong?
If thread A has modified some object inside a code block CB1 guarded by the lock and then releases the lock, and thread B enters in a code block guarded by the same lock, then thread B will see the modifications done by thread A in the code block CB1.
If two threads read and write the same shared state, then every read and write to this state should be guarded by the same lock.