ReentrantLock

ReentrantLock uses the Ganga four bridge pattern

it provides mutual exclusion and implements the lock interface

1. First, it inherits the bulk of its functionality from
   the AbstractQueuedSynchronizer class which
   provides a framework for implementing
   blocking locks and synchronizers that
   rely on First In, First Out or F.I.F.O.
   wait queues.

2. Second, it implements several lock
   acquisition models via its common
   interface.

3. The key methods in ReentrantLock are lock,
   lock interruptibly, and unlock.