在java中同时运行两个线程

import java.util.Calendar;
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;

public class timercheck extends TimerTask{
// my first thread
Thread t1 = new Thread(){
     public void run(){
        for(int i = 1;i <= 10;i++)
        {
            System.out.println(i);
        }           
     }
 };

// my second thread
Thread t2 = new Thread(){
     public void run(){
        for(int i = 11;i <= 20;i++)
        {
            System.out.println(i);
        }           
     }
 };

public static void main(String[] args){
      long ONCE_PER_DAY = 1000*60*60*24;

     Calendar calendar = Calendar.getInstance();
     calendar.set(Calendar.HOUR_OF_DAY,12);
     calendar.set(Calendar.MINUTE,05);
     calendar.set(Calendar.SECOND,00);
     Date time = calendar.getTime();

     TimerTask check  = new timercheck();
     Timer timer = new Timer();
     timer.scheduleAtFixedRate(check,time,ONCE_PER_DAY);
}

@Override    
// run method of timer task
public void run() {
    t1.start();
    t2.start();
}
}