转载：http://www.cnblogs.com/dolphin0520/p/3932921.html
java.util.concurrent.ThreadPoolExecutor类时线程池中最核心的一个类，因此如果要透彻的了解java中线程池，必须先了解这个类。下面看ThreadPoolExecutor类的具体实现源码：
在ThreadPoolExecutor类中提供了四个构造方法：
public class ThreadPoolExecutor extends AbstractExecutorService {
.....
public ThreadPoolExecutor(int corePoolSize,int maximumPoolSize,long keepAliveTime,TimeUnit unit,
BlockingQueue<Runnable> workQueue);
public ThreadPoolExecutor(int corePoolSize,int maximumPoolSize,long keepAliveTime,TimeUnit unit,
BlockingQueue<Runnable> workQueue,ThreadFactory threadFactory);
public ThreadPoolExecutor(int corePoolSize,int maximumPoolSize,long keepAliveTime,TimeUnit unit,
BlockingQueue<Runnable> workQueue,RejectedExecutionHandler handler);
public ThreadPoolExecutor(int corePoolSize,int maximumPoolSize,long keepAliveTime,TimeUnit unit,
BlockingQueue<Runnable> workQueue,ThreadFactory threadFactory,RejectedExecutionHandler handler);
...
}
从上面的代码可以得知，ThreadPoolExecutor继承了AbstractExecutorService类，并提供了四个构造器，事实上，通过观察每个构造器的源码具体实现，发现前三个构造器都是调用第四个构造器进行的初始化工作。
原文：http://www.cnblogs.com/woshimrf/p/5249753.html