假设当前线程A是生产者线程，调用await()方法后，会释放锁，并且将当前线程加入到Condition队列中。此时，消费者能获取到锁资源，然后继续执行。假设线程B是消费者线程，当添加一个元素后会调用condition#signal()方法，定义如下：
public final void signal() { if (!isHeldExclusively()) throw new IllegalMonitorStateException(); Node first = firstWaiter; if (first != null) doSignal(first); } private void doSignal(Node first) { do { if ( (firstWaiter = first.nextWaiter) == null) lastWaiter = null; first.nextWaiter = null; } while (!transferForSignal(first) && (first = firstWaiter) != null); } final boolean transferForSignal(Node node) { /* * If cannot change waitStatus, the node has been cancelled. */ if (!compareAndSetWaitStatus(node, Node.CONDITION, 0)) return false; /* * Splice onto queue and try to set waitStatus of predecessor to * indicate that thread is (probably) waiting. If cancelled or * attempt to set waitStatus fails, wake up to resync (in which * case the waitStatus can be transiently and harmlessly wrong). */ Node p = enq(node); int ws = p.waitStatus; if (ws > 0 || !compareAndSetWaitStatus(p, ws, Node.SIGNAL)) LockSupport.unpark(node.thread); return true; }执行signal()方法，会将Condition队列中的第一个节点移除，将其变为同步队列中的尾结点，如下：
至此，完成了Condition队列转换为同步队列的过程。后续流程基本就是重复以上操作。
本文详细介绍了单个Condition队列的执行流程，其实一个Lock中可以有多个Condition队列，比如：JUC中提供的LinkedBlockingDeque、ArrayBlockingQueue等