ReentrantLock

ReentrantLock lock = new ReentrantLock()

FairSync

+ final void lock(): void+ protected final boolean tryAcquire(int acquries): boolean

public final boolean hasQueuedPredecessors() { // The correctness of this depends on head being initialized // before tail and on head.next being accurate if the current // thread is first in queue. Node t = tail; // Read fields in reverse initialization order Node h = head; Node s; return h != t && ((s = h.next) == null || s.thread != Thread.currentThread());}

final void lock() {    acquire(1);}

extends

inner class

ReentrantLock

private final Sync

private final boolean parkAndCheckInterrupt() { LockSupport.park(this); return Thread.interrupted();}

sync.lock();

abstract class AbstractQueuedSynchronizerprotected boolean tryAcquire(int arg) { throw new UnsupportedOperationException();}

start

NonFairSync

+ final void lock(): void+ protected final boolean tryAcquire(int acquires):boolean

Sync

+ abstract void lock(): void+ final boolean nonfairTryAcquire(int acquires):boolean

protected final boolean tryAcquire(int acquires) {    return nonfairTryAcquire(acquires);}

lock.lock()