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While this is an acceptable compliant solution, intrinsic locks cause threads to block and may introduce contention. On the other hand, volatile-qualified shared variables do not block. Excessive synchronization can also make the program prone to deadlock. CON04-J. Synchronize using an internal private final lock object mitigates many of these problems by encapsulating the lock in a private field.
Synchronization is a more secure alternative in situations where the volatile keyword or a java.util.concurrent.atomic.Atomic* field is inappropriate, such as if a variable's new value depends on its current value. Refer to CON01-J. Ensure that compound operations on shared variables are atomic for more information.
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