摘要：如果發(fā)生了動(dòng)作，則會(huì)從等待池當(dāng)中喚醒一個(gè)線程重新恢復(fù)到狀態(tài)，如果是操作，則喚醒所有等待線程。當(dāng)時(shí)間達(dá)到時(shí)觸發(fā)線程回到工作狀態(tài)。線程終止?fàn)顟B(tài)線程結(jié)束了，就處于這種狀態(tài)，也就是方法運(yùn)行完了。線程狀態(tài)切換詳細(xì)圖線程狀態(tài)源碼

還沒(méi)調(diào)用start，或者調(diào)用了start()方法，不一定立即改變線程狀態(tài)，中間可能需要一些步驟才完成一個(gè)線程的啟動(dòng)。

start調(diào)用結(jié)束，線程由NEW變成RUNNABLE，存活著，并嘗試占用CPU資源，yield操作時(shí)，線程還是Runnable狀態(tài)，只是它有一個(gè)細(xì)節(jié)的內(nèi)部變化，做一個(gè)簡(jiǎn)單的讓步。在Java層面是Runnable的狀態(tài)，并不代表一定處于運(yùn)行中的狀態(tài)，比如BIO中，線程正阻塞在網(wǎng)絡(luò)等待的時(shí)候，看到的狀態(tài)依然是Runnable狀態(tài)，而底層線程已經(jīng)被阻塞住了。

線程被掛起了，原因通常是因?yàn)樗诘却粋€(gè)鎖，當(dāng)某個(gè)synchronized正好有線程在使用時(shí)，一個(gè)線程嘗試進(jìn)入這個(gè)臨界區(qū)，就會(huì)被阻塞，直到另一個(gè)線程走完臨界區(qū)或發(fā)生了相應(yīng)鎖對(duì)象的wait操作后，它才有機(jī)會(huì)去爭(zhēng)奪進(jìn)入臨界區(qū)的權(quán)利。當(dāng)搶到鎖之后，才會(huì)從blocked狀態(tài)恢復(fù)到runnable狀態(tài)。這個(gè)狀態(tài)它好像什么也不做一樣。

當(dāng)wait，join，park方法調(diào)用時(shí)，進(jìn)入waiting狀態(tài)。前提是這個(gè)線程已經(jīng)擁有鎖了。

blocked和waiting狀態(tài)的區(qū)別是：
A、blocked是虛擬機(jī)認(rèn)為程序還不能進(jìn)入某個(gè)區(qū)域，因?yàn)橥瑫r(shí)進(jìn)去就會(huì)有問(wèn)題，這是一塊臨界區(qū)。
B、發(fā)生wait等操作的先決條件是要進(jìn)入臨界區(qū)，也就是線程已經(jīng)拿到鎖了，自己可能進(jìn)去做了一些事情，但此時(shí)通過(guò)判定業(yè)務(wù)上的參數(shù)，發(fā)現(xiàn)還有一些其他配合的資源沒(méi)有準(zhǔn)備充分，那么自己就等等再做其他事情。

在waiting狀態(tài)下，如果發(fā)生了interrupt操作，則處于該狀態(tài)的線程在內(nèi)部會(huì)拋出一個(gè)InterruptedException，這個(gè)異常應(yīng)當(dāng)在run方法內(nèi)捕獲，使得run方法正常地執(zhí)行完成，當(dāng)然捕獲異常后，是決定讓線程繼續(xù)運(yùn)行，還是結(jié)束等要根據(jù)業(yè)務(wù)場(chǎng)景才處理。

如果發(fā)生了notify動(dòng)作，則會(huì)從等待池當(dāng)中喚醒一個(gè)線程重新恢復(fù)到Runnable狀態(tài)，如果是notifyall操作，則喚醒所有等待線程。

通過(guò)wait(t),sleep(t),join(t),parkNanos,parkUntil等方法進(jìn)入此狀態(tài)。當(dāng)時(shí)間達(dá)到時(shí)觸發(fā)線程回到工作狀態(tài)Runnable。

interrupt只對(duì)處于waiting或timed_waiting狀態(tài)的線程起作用，對(duì)其他狀態(tài)不起作用。

線程結(jié)束了，就處于這種狀態(tài)，也就是run方法運(yùn)行完了。這只是Java語(yǔ)言級(jí)別的一種狀態(tài)，在操作系統(tǒng)內(nèi)部可能已經(jīng)注銷了相應(yīng)的線程，或者將它復(fù)用給其他需要使用線程的請(qǐng)求。

詳細(xì)圖

/**
     * A thread state.  A thread can be in one of the following states:
     * 

     * 
{@link #NEW}

     *     A thread that has not yet started is in this state.
     *     
     * 
{@link #RUNNABLE}

     *     A thread executing in the Java virtual machine is in this state.
     *     
     * 
{@link #BLOCKED}

     *     A thread that is blocked waiting for a monitor lock
     *     is in this state.
     *     
     * 
{@link #WAITING}

     *     A thread that is waiting indefinitely for another thread to
     *     perform a particular action is in this state.
     *     
     * 
{@link #TIMED_WAITING}

     *     A thread that is waiting for another thread to perform an action
     *     for up to a specified waiting time is in this state.
     *     
     * 
{@link #TERMINATED}

     *     A thread that has exited is in this state.
     *     
     * 
     *
     * 

     * A thread can be in only one state at a given point in time.
     * These states are virtual machine states which do not reflect
     * any operating system thread states.
     *
     * @since   1.5
     * @see #getState
     */
    public enum State {
        /**
         * Thread state for a thread which has not yet started.
         */
        NEW,
        /**
         * Thread state for a runnable thread.  A thread in the runnable
         * state is executing in the Java virtual machine but it may
         * be waiting for other resources from the operating system
         * such as processor.
         */
        RUNNABLE,
        /**
         * Thread state for a thread blocked waiting for a monitor lock.
         * A thread in the blocked state is waiting for a monitor lock
         * to enter a synchronized block/method or
         * reenter a synchronized block/method after calling
         * {@link Object#wait() Object.wait}.
         */
        BLOCKED,
        /**
         * Thread state for a waiting thread.
         * A thread is in the waiting state due to calling one of the
         * following methods:
         * 

         *   
{@link Object#wait() Object.wait} with no timeout
         *   
{@link #join() Thread.join} with no timeout
         *   
{@link LockSupport#park() LockSupport.park}
         * 
         *
         * 
A thread in the waiting state is waiting for another thread to
         * perform a particular action.
         *
         * For example, a thread that has called Object.wait()
         * on an object is waiting for another thread to call
         * Object.notify() or Object.notifyAll() on
         * that object. A thread that has called Thread.join()
         * is waiting for a specified thread to terminate.
         */
        WAITING,
        /**
         * Thread state for a waiting thread with a specified waiting time.
         * A thread is in the timed waiting state due to calling one of
         * the following methods with a specified positive waiting time:
         * 

         *   
{@link #sleep Thread.sleep}
         *   
{@link Object#wait(long) Object.wait} with timeout
         *   
{@link #join(long) Thread.join} with timeout
         *   
{@link LockSupport#parkNanos LockSupport.parkNanos}
         *   
{@link LockSupport#parkUntil LockSupport.parkUntil}
         * 
         */
        TIMED_WAITING,
        /**
         * Thread state for a terminated thread.
         * The thread has completed execution.
         */
        TERMINATED;
    }