Java多线程实现的四种方式

1、继承Thread类：

 1 public class ThreadTest {
 2 
 3     static class ThreadA extends Thread {
 4 
 5         @Override
 6         public void run() {
 7             System.out.println(Thread.currentThread());
 8         }
 9 
10     }
11 
12     public static void main(String[] args) {
13         ThreadA a1 = new ThreadA();
14         ThreadA a2 = new ThreadA();
15         a1.start();
16         a2.start();
17     }
18 
19 }