Release the lock. Release the lock N times. Fail only upon interuption. On failure, you can be sure that it has not been acquired, and that no corresponding release should be performed. Conversely, a normal return guarantees that the acquire was successful.
Implementations generally can only attempt to return as soon as possible after the specified bound.
Also, timers in Java do not stop during garbage collection, so timeouts can occur just because a GC intervened. So, msecs arguments should be used in a coarse-grained manner. Further, implementations cannot always guarantee that this method will return at all without blocking indefinitely when used in unintended ways. For example, deadlocks may be encountered when called in an unintended context. An argument less than or equal to zero means not to wait at all.