为什么线程不等待notify（）？ [英] Why doesn't thread wait for notify()?

问题描述

为什么线程不等待 notify（）？线程启动，然后进入等待池，但它继续执行之后的那一刻。

  public class JavaApplication2 {
 public static void main（String [] args）{
 ThreadB b = new ThreadB（）; 
 synchronized（b）{
 b.start（）; 
 try {
 System.out.println（1）; 
 b.wait（）; 
} catch（InterruptedException e）{} 
 System.out.println（Total is：+ b.total）; 
} 
} 
} 
类ThreadB extends Thread {
 int total; 
 @Override 
 public void run（）{
 synchronized（this）{
 total + = 1; 
 // notify（）; 
} 
} 
} 
  

解决方案>

您正在同步线程对象本身，这是错误的用法。发生的是，死亡的线程总是在它的线程对象上调用 notify ： Thread.join 依赖于此。因此，很清楚为什么你在这里有和没有你自己的通知一样的行为。

解决方案：use用于线程协调的单独对象;这是标准做法。

Why doesn't thread wait for notify()? The thread starts and then goes to the waiting pool, but it proceeds to execute after that moment.

public class JavaApplication2 {
    public static void main(String [] args) {
       ThreadB b = new ThreadB();
       synchronized(b) {
           b.start();
           try {
              System.out.println("1");
              b.wait();
         } catch (InterruptedException e) {}
          System.out.println("Total is: " + b.total);
       }
     }
 }
  class ThreadB extends Thread {   
    int total;
      @Override
    public void run() {
        synchronized(this) {
            total += 1;
            //notify();
       }
    }
 }

解决方案

You are synchronizing on the thread object itself, which is wrong usage. What happens is that the dying thread-of-execution always calls notify on its Thread object: Thread.join relies on this. Therefore it is clear why you get the same behavior with and without your own notify in there.

Solution: use a separate object for thread coordination; this is the standard practice.

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