Package java.util.concurrent.locks
The Lock interface supports
 locking disciplines that differ in semantics (reentrant, fair, etc),
 and that can be used in non-block-structured contexts including
 hand-over-hand and lock reordering algorithms.  The main implementation
 is ReentrantLock.
 
The ReadWriteLock interface
 similarly defines locks that may be shared among readers but are
 exclusive to writers.  Only a single implementation, ReentrantReadWriteLock, is provided, since
 it covers most standard usage contexts.  But programmers may create
 their own implementations to cover nonstandard requirements.
 
The Condition interface
 describes condition variables that may be associated with Locks.
 These are similar in usage to the implicit monitors accessed using
 Object.wait, but offer extended capabilities.
 In particular, multiple Condition objects may be associated
 with a single Lock.  To avoid compatibility issues, the
 names of Condition methods are different from the
 corresponding Object versions.
 
The AbstractQueuedSynchronizer
 class serves as a useful superclass for defining locks and other
 synchronizers that rely on queuing blocked threads.  The AbstractQueuedLongSynchronizer class
 provides the same functionality but extends support to 64 bits of
 synchronization state.  Both extend class AbstractOwnableSynchronizer, a simple
 class that helps record the thread currently holding exclusive
 synchronization.  The LockSupport
 class provides lower-level blocking and unblocking support that is
 useful for those developers implementing their own customized lock
 classes.
- Since:
- 1.5
- 
Interface Summary Interface Description Condition Lock Lockimplementations provide more extensive locking operations than can be obtained usingsynchronizedmethods and statements.ReadWriteLock AReadWriteLockmaintains a pair of associatedlocks, one for read-only operations and one for writing.
- 
Class Summary Class Description AbstractOwnableSynchronizer A synchronizer that may be exclusively owned by a thread.AbstractQueuedLongSynchronizer A version ofAbstractQueuedSynchronizerin which synchronization state is maintained as along.AbstractQueuedSynchronizer Provides a framework for implementing blocking locks and related synchronizers (semaphores, events, etc) that rely on first-in-first-out (FIFO) wait queues.LockSupport Basic thread blocking primitives for creating locks and other synchronization classes.ReentrantLock A reentrant mutual exclusionLockwith the same basic behavior and semantics as the implicit monitor lock accessed usingsynchronizedmethods and statements, but with extended capabilities.ReentrantReadWriteLock An implementation ofReadWriteLocksupporting similar semantics toReentrantLock.ReentrantReadWriteLock.ReadLock The lock returned by methodReadWriteLock.readLock().ReentrantReadWriteLock.WriteLock The lock returned by methodReadWriteLock.writeLock().StampedLock A capability-based lock with three modes for controlling read/write access.