void    run()

 If this thread was constructed using a separate Runnable run object, then that Runnable object's run method is called; otherwise, this method does nothing and returns.

 void    start()

 Causes this thread to begin execution; the Java Virtual Machine calls the run method of this thread.

 public class Main {

     public static void main(String[] args) {

         Mythread t = new Mythread();

         Thread thread1 = new Thread(t);

         Thread thread2 = new Thread(t);

         System.out.println("begin = " + System.currentTimeMillis());

         thread1.setName("我是线程1");

         thread2.setName("我是线程2");

         thread1.run();

         thread2.start();

         System.out.println("end = " + System.currentTimeMillis());

     }

 }

 class Mythread extends Thread{

     public void run() {

         try {

             System.out.println("threadName: "+this.currentThread().getName()+" begin");

             Thread.sleep(1000);

             System.out.println("threadName: "+this.currentThread().getName()+" end");

         } catch (InterruptedException e) {

             e.printStackTrace();

         }

     }

 }