j.u.c： Java并发包的5大块

//TODO

Executors:

ExecutorService executor = Executors.newFixedThreadPool(10);
... newForkJoinPool()...

executor.submit (Callable<T> | Runnable)

锁

1. 内置锁

2. Reentrant-Lock

3. Stamped-Lock

4. ReadWrite-Lock

Semaphore

锁是排他的、被锁住的code block 一次只能由唯一的线程在运行。 而Semaphore则可以提供指定数量的 permits， 允许最多指定数量的线程同时访问。

适用场景：

/**
 * Whereas locks usually grant exclusive access to variables or resources,
 * a semaphore is capable of maintaining whole sets of permits.
 * This is useful in different scenarios where you have to limit the amount concurrent access
 * to certain parts of your application.
 */

Atomic Variables
很简单的样子

Concurrent Collections (线程安全的容器）