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;}

public class Test1
{public static void main(String[] args){Thread1 t1 = new Thread1();Thread2 t2 = new Thread2();t1.setThread2(t2);t1.start();t2.start();}
}//Thread1负责打印两个线程的状态。
class Thread1 extends Thread
{private Thread2 t2;public void setThread2(Thread2 t2){this.t2 = t2;}@Overridepublic void run(){System.out.println("进入t1线程");for(int i = 0; i < 5; i++){try{System.out.println("t1 的状态： " + getState());System.out.println("t2 的状态： " + t2.getState());System.out.println();//为了减少打印次数，所以t1每打印一次睡1秒Thread.sleep(1000);} catch (InterruptedException e){}}}
}class Thread2 extends Thread
{@Overridepublic void run(){System.out.println("进入t2线程，马上进入睡眠");try{//睡眠5秒钟。sleep(5000);} catch (InterruptedException e){e.printStackTrace();}System.out.println("t2睡眠结束");}
}

public class Test1
{public static void main(String[] args){Thread1 t1 = new Thread1();Thread2 t2 = new Thread2();Thread3 t3 = new Thread3();//t1需要持有t2,t3的引用，以便打印他们的状态。
        t1.setThread2(t2,t3);//t2需要持有t3的引用，以便t3能够在t2执行时加入(调用join()方法)
        t2.setTh3(t3);t1.start();t2.start();}
}//Thread1负责打印所有线程的状态。
class Thread1 extends Thread
{private Thread2 t2;private Thread3 t3;public void setThread2(Thread2 t2, Thread3 t3){this.t2 = t2;this.t3 = t3;}@Overridepublic void run(){System.out.println("进入t1线程");for(int i = 0; i < 5; i++){try{System.out.println("t1 的状态： " + getState());System.out.println("t2 的状态： " + t2.getState());System.out.println("t3 的状态： " + t3.getState());System.out.println();//为了减少打印次数，所以t1每打印一次睡1秒Thread.sleep(1000);} catch (InterruptedException e){}}}
}class Thread2 extends Thread
{private Thread3 t3;public void setTh3(Thread3 t3){this.t3 = t3;}//当进入t2线程以后马上启动t3线程并调用join()方法。
    @Overridepublic void run(){System.out.println("进入t2线程，t3准备加入(调用join()方法)");t3.start();try{t3.join();} catch (InterruptedException e){e.printStackTrace();}System.out.println("t2执行结束");}
}
class Thread3 extends Thread
{@Overridepublic void run(){System.out.println("进入t3线程，准备睡眠");//本来是想让t3线程做加法运算的，奈何电脑算太快了，所以改为睡眠。因为睡眠不释放锁，所以效果一样。try{sleep(5000);} catch (InterruptedException e){e.printStackTrace();}System.out.println("t3线程结束");}
}

package com.zcd.observe;public class Test1
{public static void main(String[] args){Thread1 t1 = new Thread1();Thread2 t2 = new Thread2();//t1需要持有t2,以便打印状态，和控制它恢复运行。
        t1.setThread2(t2);t1.start();t2.start();}
}//Thread1负责打印所有线程的状态。
class Thread1 extends Thread
{private Thread2 t2;public void setThread2(Thread2 t2){this.t2 = t2;}@Overridepublic void run(){System.out.println("进入t1线程");for(int i = 0; i < 6; i++){try{System.out.println("t1 的状态： " + getState());System.out.println("t2 的状态： " + t2.getState());System.out.println();if(i == 3){//恢复t2的运行。
                    t2.resume();}//为了减少打印次数，所以t1每打印一次睡1秒Thread.sleep(1000);} catch (InterruptedException e){}}}
}class Thread2 extends Thread
{@Overridepublic void run(){System.out.println("进入t2线程，挂起");//将线程挂起。让t1来控制它的恢复运行。
        suspend();System.out.println("t2已经恢复运行");System.out.println("t2正在打印1");System.out.println("t2正在打印2");System.out.println("t2正在打印3");System.out.println("t2线程结束");}
}

package com.zcd.observe;import java.util.Scanner;public class Test1
{public static void main(String[] args){Thread1 t1 = new Thread1();Thread2 t2 = new Thread2();t1.setThread2(t2);t1.start();t2.start();}
}//Thread1负责打印所有线程的状态。
class Thread1 extends Thread
{private Thread2 t2;public void setThread2(Thread2 t2){this.t2 = t2;}@Overridepublic void run(){System.out.println("进入t1线程");for(int i = 0; i < 6; i++){try{System.out.println("t1 的状态： " + getState());System.out.println("t2 的状态： " + t2.getState());System.out.println();//为了减少打印次数，所以t1每打印一次睡1秒Thread.sleep(1000);} catch (InterruptedException e){}}System.out.println("进入t1线程结束");}
}class Thread2 extends Thread
{@Overridepublic void run(){System.out.println("进入t2线程");//让线程进入I/OSystem.out.println("请输入数据：");Scanner scan = new Scanner(System.in);String read = scan.nextLine();System.out.println("您输入的数据为："+read); System.out.println("t2线程结束");}
}