求注释里面的问题？为什么会报错？详解必采纳

Question

为什么在这里会报错？？哪里有问题吗？线程到底该怎么写啊？写线程得分开类写吗？

Answer 1

public class A implements Runnable {
    
    @Override
    public void run() {
        try {
            Thread.sleep(2000);
            System.out.println("邮件发送模拟程序，执行完毕");
        } catch (Exception e) {
            System.out.println("线程中断异常");
            e.printStackTrace();
        }
        
    }
    
    public class EmilThreadRun {
        public void registerUser() {
            System.out.println("用户注册成功");
        }
    }
    
    public static void main(String[] args) {
        A a = new A();
        EmilThreadRun emilThreadRun = a.new EmilThreadRun();
        Thread thread = new Thread(a);
        emilThreadRun.registerUser();
        thread.start();
        System.out.println("用户电子邮箱注册运行成功");
    }
    
    

}