看了ArrayBlockingQueue的源碼public?class?ArrayBlockingQueue<E>?extends?AbstractQueue<E>????????implements?BlockingQueue<E>,?java.io.Serializable?{ ? ????final?Object[]?items;?? ????int?takeIndex;?? ????int?putIndex;??? ????int?count;???? ????final?ReentrantLock?lock;????/**notEmpty條件對象，用于通知take方法隊列已有元素，可執行獲取操作?*/ ????private?final?Condition?notEmpty;???? ????private?final?Condition?notFull;??? ???????迭代器 ?????*/ ????transient?Itrs?itrs?=?null; ????public?void?put(E?e)?throws?InterruptedException?{ ?????checkNotNull(e);?????? ?????final?ReentrantLock?lock?=?this.lock;??//?？？？？？？？？ ??????lock.lockInterruptibly(); ??????try?{?????????? ??????????while?(count?==?items.length)??????????????//將當前調用線程掛起，添加到notFull條件隊列中等待喚醒 ??????????????notFull.await(); ??????????enqueue(e);//如果隊列沒有滿直接添加。。 ??????}?finally?{ ??????????lock.unlock(); ??????} ??} }為甚么類的屬性里沒有ReentrantLock lock = new ReentrantLock();卻可以在put()中直接指定ReentrantLock lock=this.lock;?