代码分析Java中线程的等待与唤醒

class ThreadA extends Thread{
 
  public ThreadA(String name) {
    super(name);
  }
 
  public void run() {
    synchronized (this) {
      System.out.println(Thread.currentThread().getName()+" call notify()");
      notify();
    }
  }
}
public class WaitTest {
  public static void main(String[] args) {
    ThreadA t1 = new ThreadA("t1");
    synchronized(t1) {
      try {
        // 启动“线程t1”
        System.out.println(Thread.currentThread().getName()+" start t1");
        t1.start();
 
        // 主线程等待t1通过notify()唤醒。
        System.out.println(Thread.currentThread().getName()+" wait()");
        t1.wait();
 
        System.out.println(Thread.currentThread().getName()+" continue");
      } catch (InterruptedException e) {
        e.printStackTrace();
      }
    }
  }
}

public class SleepLockTest{ 
  private static Object obj = new Object();
  public static void main(String[] args){ 
    ThreadA t1 = new ThreadA("t1"); 
    ThreadA t2 = new ThreadA("t2"); 
    t1.start(); 
    t2.start();
  } 
  static class ThreadA extends Thread{
    public ThreadA(String name){ 
      super(name); 
    } 
    public void run(){ 
      synchronized (obj) {
        try {
          for(int i=0; i <10; i++){ 
            System.out.printf("%s: %d\n", this.getName(), i); 
            // i能被4整除时，休眠100毫秒
            if (i%4 == 0)
              Thread.sleep(100);
          }
        } catch (InterruptedException e) {
          e.printStackTrace();
        }
      }
    } 
  } 
}