哪一个构造函数
public ArrayBlockingQueue(int capacity, boolean fair,Collection<? extends E> c) {this(capacity, fair);final ReentrantLock lock = this.lock;lock.lock(); // Lock only for visibility, not mutual exclusiontry {final Object[] items = this.items;int i = 0;try {for (E e : c)items[i++] = Objects.requireNonNull(e);} catch (ArrayIndexOutOfBoundsException ex) {throw new IllegalArgumentException();}count = i;putIndex = (i == capacity) ? 0 : i;} finally {lock.unlock();}}
原因
在ArrayBlockingQueue
的带有三个参数的构造函数中,加锁的目的不是为了实现互斥(即不是为了阻止多个线程同时进入关键区域)。相反,它主要用于确保在构造函数中的可见性,而不是互斥。