在线JDK地址： 

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英文：  http://tool.oschina.net/apidocs/apidoc?api=jdk_7u4

在线源码地址：java.util.concurrent.Executors    java.util.concurrent.ThreadPoolExecutor

java.util.concurrent.Executors
Executors中 newFixedThreadPool 方法

    public static ExecutorService newFixedThreadPool(int nThreads) {
        return new ThreadPoolExecutor(nThreads, nThreads,
                                      0L, TimeUnit.MILLISECONDS,
                                      new LinkedBlockingQueue<Runnable>());
    }
    public static ExecutorService newFixedThreadPool(int nThreads, ThreadFactory threadFactory) {
        return new ThreadPoolExecutor(nThreads, nThreads,
                                      0L, TimeUnit.MILLISECONDS,
                                      new LinkedBlockingQueue<Runnable>(),
                                      threadFactory);
    }

Executors中 newSingleThreadExecutor 方法

    public static ExecutorService newSingleThreadExecutor() {
        return new FinalizableDelegatedExecutorService
            (new ThreadPoolExecutor(1, 1,
                                    0L, TimeUnit.MILLISECONDS,
                                    new LinkedBlockingQueue<Runnable>()));
    }
    public static ExecutorService newSingleThreadExecutor(ThreadFactory threadFactory) {
        return new FinalizableDelegatedExecutorService
            (new ThreadPoolExecutor(1, 1,
                                    0L, TimeUnit.MILLISECONDS,
                                    new LinkedBlockingQueue<Runnable>(),
                                    threadFactory));
    }

Executors中 newCachedThreadPool 方法

    public static ExecutorService newCachedThreadPool() {
        return new ThreadPoolExecutor(0, Integer.MAX_VALUE,
                                      60L, TimeUnit.SECONDS,
                                      new SynchronousQueue<Runnable>());
    }
    public static ExecutorService newCachedThreadPool(ThreadFactory threadFactory) {
        return new ThreadPoolExecutor(0, Integer.MAX_VALUE,
                                      60L, TimeUnit.SECONDS,
                                      new SynchronousQueue<Runnable>(),
                                      threadFactory);
    }

Executors中 newScheduledThreadPool 方法

    public static ScheduledExecutorService newScheduledThreadPool(int corePoolSize) {
        return new ScheduledThreadPoolExecutor(corePoolSize);
    }
    public static ScheduledExecutorService newScheduledThreadPool(int corePoolSize, ThreadFactory threadFactory) {
        return new ScheduledThreadPoolExecutor(corePoolSize, threadFactory);
    }

java.util.concurrent.ThreadPoolExecutor

ThreadPoolExecutor 构造方法如下：

    public ThreadPoolExecutor(int corePoolSize,
                              int maximumPoolSize,
                              long keepAliveTime,
                              TimeUnit unit,
                              BlockingQueue<Runnable> workQueue) {
        this(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue,
             Executors.defaultThreadFactory(), defaultHandler);
    }
    public ThreadPoolExecutor(int corePoolSize,
                              int maximumPoolSize,
                              long keepAliveTime,
                              TimeUnit unit,
                              BlockingQueue<Runnable> workQueue,
                              ThreadFactory threadFactory) {
        this(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue,
             threadFactory, defaultHandler);
    }

    public ThreadPoolExecutor(int corePoolSize,
                              int maximumPoolSize,
                              long keepAliveTime,
                              TimeUnit unit,
                              BlockingQueue<Runnable> workQueue,
                              ThreadFactory threadFactory,
                              RejectedExecutionHandler handler) {
        if (corePoolSize < 0 ||
            maximumPoolSize <= 0 ||
            maximumPoolSize < corePoolSize ||
            keepAliveTime < 0)
            throw new IllegalArgumentException();
        if (workQueue == null || threadFactory == null || handler == null)
            throw new NullPointerException();
        this.corePoolSize = corePoolSize;
        this.maximumPoolSize = maximumPoolSize;
        this.workQueue = workQueue;
        this.keepAliveTime = unit.toNanos(keepAliveTime);
        this.threadFactory = threadFactory;
        this.handler = handler;
    }
    /**
     * Core pool size, updated only while holding mainLock, but
     * volatile to allow concurrent readability even during updates.
     */
    private volatile int   corePoolSize;
    /**
     * Maximum pool size, updated only while holding mainLock but
     * volatile to allow concurrent readability even during updates.
     */
    private volatile int   maximumPoolSize;
    /**
     * The queue used for holding tasks and handing off to worker
     * threads.  Note that when using this queue, we do not require
     * that workQueue.poll() returning null necessarily means that
     * workQueue.isEmpty(), so must sometimes check both. This
     * accommodates special-purpose queues such as DelayQueues for
     * which poll() is allowed to return null even if it may later
     * return non-null when delays expire.
     */
    private final BlockingQueue<Runnable> workQueue;
    /**
     * Timeout in nanoseconds for idle threads waiting for work.
     * Threads use this timeout when there are more than corePoolSize
     * present or if allowCoreThreadTimeOut. Otherwise they wait
     * forever for new work.
     */
    private volatile long  keepAliveTime;
    /**
     * Factory for new threads. All threads are created using this
     * factory (via method addThread).  All callers must be prepared
     * for addThread to fail by returning null, which may reflect a
     * system or user's policy limiting the number of threads.  Even
     * though it is not treated as an error, failure to create threads
     * may result in new tasks being rejected or existing ones
     * remaining stuck in the queue. On the other hand, no special
     * precautions exist to handle OutOfMemoryErrors that might be
     * thrown while trying to create threads, since there is generally
     * no recourse from within this class.
     */
    private volatile ThreadFactory threadFactory;
    /**
     * Handler called when saturated or shutdown in execute.
     */
    private volatile RejectedExecutionHandler handler;

ThreadPoolExecutor  中 execute 方法如下：

    public void execute(Runnable command) {
        if (command == null)
            throw new NullPointerException();
        if (poolSize >= corePoolSize || !addIfUnderCorePoolSize(command)) {
            if (runState == RUNNING && workQueue.offer(command)) {
                if (runState != RUNNING || poolSize == 0)
                    ensureQueuedTaskHandled(command);
            }
            else if (!addIfUnderMaximumPoolSize(command))
                reject(command); // is shutdown or saturated
        }
    }
    
    private boolean addIfUnderCorePoolSize(Runnable firstTask) {
        Thread t = null;
        final ReentrantLock mainLock = this.mainLock;
        mainLock.lock();
        try {
            if (poolSize < corePoolSize && runState == RUNNING)
                t = addThread(firstTask);
        } finally {
            mainLock.unlock();
        }
        return t != null;
    }
    
    private Thread addThread(Runnable firstTask) {
        Worker w = new Worker(firstTask);
        Thread t = threadFactory.newThread(w);
        boolean workerStarted = false;
        if (t != null) {
            if (t.isAlive()) // precheck that t is startable
                throw new IllegalThreadStateException();
            w.thread = t;
            workers.add(w);
            int nt = ++poolSize;
            if (nt > largestPoolSize)
                largestPoolSize = nt;
            try {
                t.start();
                workerStarted = true;
            }
            finally {
                if (!workerStarted)
                    workers.remove(w);
            }
        }
        return t;
    }
    
    /**
     * Lock held on updates to poolSize, corePoolSize,
     * maximumPoolSize, runState, and workers set.
     */
    private final ReentrantLock mainLock = new ReentrantLock();

    volatile int runState;
    static final int RUNNING    = 0;
    static final int SHUTDOWN   = 1;
    static final int STOP       = 2;
    static final int TERMINATED = 3;

ThreadPoolExecutor  中 其他方法：

    /**
     * Set containing all worker threads in pool. Accessed only when
     * holding mainLock.
     */
    private final HashSet<Worker> workers = new HashSet<Worker>();
    /**
     * The queue used for holding tasks and handing off to worker
     * threads.  Note that when using this queue, we do not require
     * that workQueue.poll() returning null necessarily means that
     * workQueue.isEmpty(), so must sometimes check both. This
     * accommodates special-purpose queues such as DelayQueues for
     * which poll() is allowed to return null even if it may later
     * return non-null when delays expire.
     */
    private final BlockingQueue<Runnable> workQueue;
    
    /**
     * Counter for completed tasks. Updated only on termination of
     * worker threads.
     */
    private long completedTaskCount;
    
    public int getActiveCount() {
        final ReentrantLock mainLock = this.mainLock;
        mainLock.lock();
        try {
            int n = 0;
            for (Worker w : workers) {
                if (w.isActive())
                    ++n;
            }
            return n;
        } finally {
            mainLock.unlock();
        }
    }
    public long getCompletedTaskCount() {
        final ReentrantLock mainLock = this.mainLock;
        mainLock.lock();
        try {
            long n = completedTaskCount;
            for (Worker w : workers)
                n += w.completedTasks;
            return n;
        } finally {
            mainLock.unlock();
        }
    }
    public long getTaskCount() {
        final ReentrantLock mainLock = this.mainLock;
        mainLock.lock();
        try {
            long n = completedTaskCount;
            for (Worker w : workers) {
                n += w.completedTasks;
                if (w.isActive())
                    ++n;
            }
            return n + workQueue.size();
        } finally {
            mainLock.unlock();
        }
    }