java.lang.Thread.State
成员内部类
NEW：还未启动
Thread state for a thread which has not yet started.
RUNNABLE：正在jvm中运行，但是可能正在等待操作系统的其他资源
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.
BLOCKED：受阻塞，并且正在等待监视器锁
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}.
WAITING：处于等待状态的线程，正在等待另一个线程执行特定的操作
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.
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.
TIMED_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}
TERMINATED
Thread state for a terminated thread.
The thread has completed execution.
Thread start()
sleep() sleep(?)
join()
Object wait() notify() notifyAll()
wait(?)
新建（new）
可运行（Runnable）
阻塞（block）
死亡（dead）
新创建一个线程，线程处于新建状态（new）
调用线程的start()方法，线程进入可运行状态（Runnable），该线程位于可运行线程池中，等待被线程调度选中，获取CPU使用权，此时线程处于就绪状态
处于就绪状态的线程一点获得CPU使用权，进入运行状态
一个线程在执行过程中，想获得某一资源的锁，但是该资源又被其它线程占用，此时，当前线程处于阻塞状态（例如，进入一个同步方法或者同步代码块，要先获得锁）
一个线程处于等待（waiting）状态，表示该线程正在等待其它线程执行特定的操作
例如，一个线程调用了Object类的空参的wait方法，表示该线程等待其它线程调用该对象的notify或者notifyAll方法
一个线程调用了Thread类的空参的join方法，表示该线程在等待一个特定的线程终止
一个线程处于超时等待状态（timed_waiting），和waiting不同的是，将在特定的时间内自行返回
一个线程执行完毕，进入终止状态（terminated）