???????????????????????????????????????????????????????е????????????????????????????????

import java.util.concurrent.TimeUnit;
public class  Test  {
  
   
    public  static void  main(String[] args){
        //??????????????????????????main???????????        
        Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
        Thread  myThread=new Thread(new Runnable(){
            public void run(){
                while(true)
                {  
                    System.out.println("i will wait for you in shangling");
                    try {
                        TimeUnit.MILLISECONDS.sleep(100);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        });
        myThread.setDaemon(true); //???ú?????????д??start()????????棬????????Ч??
        myThread.setPriority(Thread.MAX_PRIORITY);
        myThread.start();
        Thread userThread = new Thread(new Runnable(){
            public void run(){
                for(int i=0;i<5;i++)
                    System.out.println("this is a user Thread");
                                   
            }
        });
        userThread.setPriority(Thread.MAX_PRIORITY);
        userThread.start();
            
        System.out.println("the main thread is end" );
    }   
}

??????????????????????????????????????????????????????????????????????????????е???????????????????????????????ú???????еt???????????????????????????????????????????main?????????????sleep?????????????????

??????????????????????sleep??????????????????????????????????????????????????????????????????????????????????????????????????鷢????