//TODO
线程池
<pre>public ThreadPoolExecutor(int corePoolSize,
int maximumPoolSize,
long keepAliveTime,
TimeUnit unit,
BlockingQueue<Runnable> workQueue,
RejectedExecutionHandler handler)</pre>
Executors.newFixedThreadPool(int nThreads)
Executors.newCachedThreadPool()
Executors.newSingleThreadScheduledExecutor()
Executors.newScheduledThreadPool(int corePoolSize)
队列
BlockingQueue<E>
ArrayBlockingQueue<E>
LinkedBlockingQueue<E>
...
广义上的内置条件队列：Condition
