java - 多线程程序每次都有不同的输出

Question

当我尝试多次执行以下多线程代码时，输​​出与前一个不同。这是因为 JVM 行为还是其他原因。请帮我一个。

program:


package example.thread.com;

class MyThread1 implements Runnable {
    Thread t;

    MyThread1(String s) {
        t = new Thread(this, s);
        t.start();
    }

    public void run() {
        for (int i = 0; i < 5; i++) {
            System.out.println("Thread Name  :"
                    + Thread.currentThread().getName());
            try {
                Thread.sleep(2000);
            } catch (Exception e) {
            }
        }
    }
}


public class RunnableThread1 {
    public static void main(String args[]) {
        System.out.println("Thread Name :" + Thread.currentThread().getName());
        MyThread1 m1 = new MyThread1("My Thread 1");
        MyThread1 m2 = new MyThread1("My Thread 2");
    }
}

输出:如果我第一次运行

Thread Name :main
Thread Name  :My Thread 1
Thread Name  :My Thread 2
Thread Name  :My Thread 1
Thread Name  :My Thread 2
Thread Name  :My Thread 2
Thread Name  :My Thread 1
Thread Name  :My Thread 1
Thread Name  :My Thread 2
Thread Name  :My Thread 1
Thread Name  :My Thread 2

输出:如果我第二次运行

Thread Name :main
Thread Name  :My Thread 2
Thread Name  :My Thread 1
Thread Name  :My Thread 2
Thread Name  :My Thread 1
Thread Name  :My Thread 2
Thread Name  :My Thread 1
Thread Name  :My Thread 1
Thread Name  :My Thread 2
Thread Name  :My Thread 1
Thread Name  :My Thread 2

输出:如果我第三次运行

Thread Name :main
Thread Name  :My Thread 1
Thread Name  :My Thread 2
Thread Name  :My Thread 2
Thread Name  :My Thread 1
Thread Name  :My Thread 1
Thread Name  :My Thread 2
Thread Name  :My Thread 2
Thread Name  :My Thread 1
Thread Name  :My Thread 2
Thread Name  :My Thread 1

像这样请推荐......

Answer 1

这正是示例的要点。它表明线程是随心所欲地调度的，并且不能保证输出按顺序发生。

在其他编程语言和系统中，期望损坏的输出并非没有道理，例如:

Thread Name :main
Thread Name  :My Thread 1
Thread NThread Name  :My Thread 2ame  :My Thread 2
Thread Name  :My Thread 1
Thread Name  :My Thread 2
Thread Name  :My Thread 1
ThreaThread Name  :My d Name  :My ThrThread 2ead 1
Thread Name  :My Thread 2
Thread Name  :My Thread 1