public ThreadPoolExecutor(int corePoolSize,int maximumPoolSize,long keepAliveTime,TimeUnit unit,
BlockingQueue<Runnable> workQueue,ThreadFactory threadFactory,RejectedExecutionHandler handler)

public void execute(Runnable command) {if (command == null)throw new NullPointerException();/** Proceed in 3 steps:** 1. If fewer than corePoolSize threads are running, try to* start a new thread with the given command as its first* task.  The call to addWorker atomically checks runState and* workerCount, and so prevents false alarms that would add* threads when it shouldn't, by returning false.** 2. If a task can be successfully queued, then we still need* to double-check whether we should have added a thread* (because existing ones died since last checking) or that* the pool shut down since entry into this method. So we* recheck state and if necessary roll back the enqueuing if* stopped, or start a new thread if there are none.** 3. If we cannot queue task, then we try to add a new* thread.  If it fails, we know we are shut down or saturated* and so reject the task.*/int c = ctl.get();//workerCountOf(c)用于获取线程池中当前线程数目if (workerCountOf(c) < corePoolSize) {//addWorker(command,true)创建新的线程执行该任务if (addWorker(command, true))return;c = ctl.get();}//当线程数目大于等于corePoolSize时，首先尝试将任务添加到任务缓存队列中if (isRunning(c) && workQueue.offer(command)) {int recheck = ctl.get();if (! isRunning(recheck) && remove(command))reject(command);else if (workerCountOf(recheck) == 0)addWorker(null, false);}//如果任务缓存队列已满，尝试创建新的线程else if (!addWorker(command, false))reject(command);}

private boolean addWorker(Runnable firstTask, boolean core) {retry:for (;;) {........................................................................for (;;) {int wc = workerCountOf(c);//当core=true时，如果线程数目小于corePoolSize，程序继续执行，创建新线程；当core=false时，如果线程数目大于等于//maximumPoolSize，程序终止执行，返回false,不会创建新的线程。if (wc >= CAPACITY ||wc >= (core ? corePoolSize : maximumPoolSize))return false;if (compareAndIncrementWorkerCount(c))break retry;c = ctl.get();  // Re-read ctlif (runStateOf(c) != rs)continue retry;// else CAS failed due to workerCount change; retry inner loop
            }}boolean workerStarted = false;boolean workerAdded = false;Worker w = null;try {//为任务创建一个新的线程w = new Worker(firstTask);..............................................} finally {if (! workerStarted)addWorkerFailed(w);}return workerStarted;}

newCachedThreadPool();

newFixedThreadPool(int nThreads);