详解Java线程的几种状态

/**
 * A thread state.  A thread can be in one of the following states:
 * <ul>
 * <li>{@link #NEW}<br>
 *     A thread that has not yet started is in this state.
 *     </li>
 * <li>{@link #RUNNABLE}<br>
 *     A thread executing in the Java virtual machine is in this state.
 *     </li>
 * <li>{@link #BLOCKED}<br>
 *     A thread that is blocked waiting for a monitor lock
 *     is in this state.
 *     </li>
 * <li>{@link #WAITING}<br>
 *     A thread that is waiting indefinitely for another thread to
 *     perform a particular action is in this state.
 *     </li>
 * <li>{@link #TIMED_WAITING}<br>
 *     A thread that is waiting for another thread to perform an action
 *     for up to a specified waiting time is in this state.
 *     </li>
 * <li>{@link #TERMINATED}<br>
 *     A thread that has exited is in this state.
 *     </li>
 * </ul>
 *
 * <p>
 * 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:
     * <ul>
     *   <li>{@link Object#wait() Object.wait} with no timeout</li>
     *   <li>{@link #join() Thread.join} with no timeout</li>
     *   <li>{@link LockSupport#park() LockSupport.park}</li>
     * </ul>
     *
     * <p>A thread in the waiting state is waiting for another thread to
     * perform a particular action.
     *
     * For example, a thread that has called <tt>Object.wait()</tt>
     * on an object is waiting for another thread to call
     * <tt>Object.notify()</tt> or <tt>Object.notifyAll()</tt> on
     * that object. A thread that has called <tt>Thread.join()</tt>
     * 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:
     * <ul>
     *   <li>{@link #sleep Thread.sleep}</li>
     *   <li>{@link Object#wait(long) Object.wait} with timeout</li>
     *   <li>{@link #join(long) Thread.join} with timeout</li>
     *   <li>{@link LockSupport#parkNanos LockSupport.parkNanos}</li>
     *   <li>{@link LockSupport#parkUntil LockSupport.parkUntil}</li>
     * </ul>
     */
    TIMED_WAITING,
    /**
     * Thread state for a terminated thread.
     * The thread has completed execution.
     */
    TERMINATED;
}

Thread thread = new Thread();

Thread thread = new Thread();
thread.start();
或
thread.run();

/**
 * Causes this thread to begin execution; the Java Virtual Machine
 * calls the <code>run</code> method of this thread.
 * <p>
 * 翻译：使此线程开始执行;Java虚拟机调用该线程的run方法。
 * The result is that two threads are running concurrently: the
 * current thread (which returns from the call to the
 * <code>start</code> method) and the other thread (which executes its
 * <code>run</code> method).
 * 翻译：结果是两个线程同时运行:当前线程(从调用start方法返回)和另一个线程(执行其run方法)。
 * <p>
 * It is never legal to start a thread more than once.
 * In particular, a thread may not be restarted once it has completed
 * execution.
 * 翻译：线程启动一次以上是不合法的。 特别是，线程在完成执行后可能不会重新启动。
 */
public synchronized void start() {
    if (threadStatus != 0)
        throw new IllegalThreadStateException();
    /* 通知该组该线程即将启动，以便将其添加到该组的线程列表中，并且该组的未启动计数可以减少。 */
    group.add(this);
    boolean started = false;
    try {
        start0();
        started = true;
    } finally {
        try {
            if (!started) {
                group.threadStartFailed(this);
            }
        } catch (Throwable ignore) {
            /* do nothing. If start0 threw a Throwable then
              it will be passed up the call stack */
        }
    }
}
/**
 * If this thread was constructed using a separate
 * <code>Runnable</code> run object, then that
 * <code>Runnable</code> object's <code>run</code> method is called;
 * otherwise, this method does nothing and returns.
 * 翻译：如果这个线程是使用一个单独的Runnable 对象构造的，那么Runnable对象的run方法被调用;否则，此方法不执 
 * 行任何操作并返回。
 * <p>
 * Subclasses of <code>Thread</code> should override this method.
 * 翻译：Thread的子类应该覆盖这个方法。  
 */
@Override
public void run() {
    if (target != null) {
        target.run();
    }
}

Object.wait();
thread.interrupt()

Object.wait();
或
thread.join()
或(锁支持)
LockSupport.park()

Object.notify() 
或
Object.notifyAll()

Thread.sleep()
或
Object.wait()
或
Thread.join()
或
LockSupport.parkNanos
或
LockSupport.parkUntil

thread.stop();