java - 为什么线程执行在下一行执行之前就完成了 [英] java - Why the thread execution was finished before the next line was executed

问题描述

我正在一个新线程中编写一个简单的算法.我想知道为什么后面的代码要等到线程完成才能运行.这是一个执行相同操作的简单程序.

I am writing a simple algorithm in a new thread. I wonder why the code that follows waits until the thread is finished in order to run. Here is a simple program that does the same.

public static void main(String[] args) {
    final String[] strings = new String[10];

    new Thread(new Runnable() {
        @Override
        public void run() {
            for (int i = 0; i < 10; i++) {
                strings[i] = String.valueOf(i);
                Thread.sleep(10000); // in real code this is wrapped in a simple try catch
            }
        }
    }).run();

    for (String string : strings) {
        System.out.print(string);
    }
}

线程休眠 10 秒，但最后一次迭代是在线程运行完成后执行的.
我什至可以延长睡眠时间.但下一行(最后一次迭代)在线程完成之前不会执行.
这是为什么?

The thread sleeps 10 seconds and yet the last iteration was executed after the thread finished running.
I can even extend the sleep time. but the next line (the final iteration) is not executed until the thread finished.
Why is that?

结果是0 1 2 3 4 5 6 7 8 9

The result is 0 1 2 3 4 5 6 7 8 9

推荐答案

您不会产生线程，因为您只是直接调用 run 方法.您需要改为调用 start 方法.

You are not spawning a thread as you just call run method directly. You need to call start method instead.

当您调用start 方法时，JVM 会产生一个新线程并调用Runnable 对象的run 方法.直接调用run方法和调用其他普通方法类似，没有新线程.

When you call start method, JVM spawns a new thread and calls the run method of the Runnable object. Calling run method directly is similar to calling any other normal method, no new thread.

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