java多线程基础：线程的状态

打开jdk源码，在Thread类中找到State枚举类。

 /**
     * 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 {
      
        NEW,

   
        RUNNABLE,

   
        BLOCKED,

    
        WAITING,


        TIMED_WAITING,

    
        TERMINATED;
    }

一共有6个状态。

NEW：初始状态，线程被构造，还未执行start（）方法。（在构造方法中是这个状态）

RUNNABLE:运行状态，java 中把就绪和运行两种状态都成为运行中。（正常运行中是这个状态）

BLOCKED:堵塞状态，表示线程堵塞于锁.。（等待锁是这个状态）

WAITTING:等待状态，表示线程进入等待需要其他线程唤醒（调用wait后是这个状态）

TIME_WAITTING:超时等待状态，不同于WAITTING，到达指定时间，自动返回。（wait(long)是这个状态）

TERMINATED:终止状态，代表当前线程执行结束。（线程结束）