See: Description
| Interface | Description | 
|---|---|
| Condition | |
| Lock | Lockimplementations provide more extensive locking
 operations than can be obtained usingsynchronizedmethods
 and statements. | 
| ReadWriteLock | A  ReadWriteLockmaintains a pair of associatedlocks, one for read-only operations and one for writing. | 
| Class | Description | 
|---|---|
| AbstractOwnableSynchronizer | A synchronizer that may be exclusively owned by a thread. | 
| AbstractQueuedLongSynchronizer | A version of  AbstractQueuedSynchronizerin
 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 exclusion  Lockwith the same basic
 behavior and semantics as the implicit monitor lock accessed usingsynchronizedmethods and statements, but with extended
 capabilities. | 
| ReentrantReadWriteLock | An implementation of  ReadWriteLocksupporting similar
 semantics toReentrantLock. | 
| ReentrantReadWriteLock.ReadLock | The lock returned by method  ReentrantReadWriteLock.readLock(). | 
| ReentrantReadWriteLock.WriteLock | The lock returned by method  ReentrantReadWriteLock.writeLock(). | 
| StampedLock | A capability-based lock with three modes for controlling read/write
 access. | 
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.
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For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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