用代码解析Java线程状态变换过程

public class TestState {
  public static void main(String[] args) {
    Thread thread = new Thread(()->{
      for (int i = 0; i < 5; i++) {
        try {
          Thread.sleep(1000);
        } catch (InterruptedException e) {
          e.printStackTrace();
        }
      }
      System.out.println("/////");
    });

    //观察线程状态
    Thread.State state = thread.getState();
    System.out.println(state); //New状态

    thread.start();
    state = thread.getState();
    System.out.println(state);//Run状态

    while (state!=Thread.State.TERMINATED){
      try {
        Thread.sleep(100);
      } catch (InterruptedException e) {
        e.printStackTrace();
      }
      state = thread.getState();//更新线程状态
      System.out.println(state);//输出状态
    }
  }
}

public class TestYield {
  public static void main(String[] args) {
    MyYield myYield = new MyYield();

    new Thread(myYield,"a").start();
    new Thread(myYield,"b").start();
  }
}

class MyYield implements Runnable{
  @Override
  public void run() {
    System.out.println(Thread.currentThread().getName()+"线程开始执行");
    Thread.yield();
    System.out.println(Thread.currentThread().getName()+"线程停止执行");
  }
}

public class TestJoin implements Runnable{
  @Override
  public void run() {
    for (int i = 0; i < 1000; i++) {
      System.out.println("强制执行线程来了"+i);
    }
  }

  public static void main(String[] args) throws Exception{
    TestJoin testJoin = new TestJoin();
    Thread thread = new Thread(testJoin);
    thread.start();

    for (int i = 0; i < 500; i++) {
      if(i==200){
        thread.join();
      }
      System.out.println("主线程"+i);
    }
  }
}