如何确定线程的执行顺序

Question

package com.oracle.thread;

import java.util.concurrent.CountDownLatch;

public class PrimeNumber implements Runnable{

int num;

static int sum = 0;

public PrimeNumber(int num) {

this.num=num;

}

final Integer mutex = 1;

CountDownLatch latch = new CountDownLatch(3) ;

@Override

public  void run() {

try {

synchronized (mutex) {

int i = num-1000+1;

while(i<num){

if(isPrime(i)){

System.out.println(Thread.currentThread().getName()+":"+i);

sum++;

}

i++;

}

}

} catch (Exception e) {

}finally {

latch.countDown();

System.out.println(sum);

}

}

public static boolean isPrime(int n){

for(int i = 2;i<n ;i++){

if(n%i==0)

return false;

}

return  true;

}

public static void main(String[] args) {

PrimeNumber p1 = new PrimeNumber(1000);

PrimeNumber p2 = new PrimeNumber(2000);

PrimeNumber p3 = new PrimeNumber(3000);

Thread t1 = new Thread(p1,"线程1");

t1.setPriority(Thread.MAX_PRIORITY);

Thread t2 = new Thread(p2,"线程2");

t2.setPriority(Thread.NORM_PRIORITY);

Thread t3 = new Thread(p3,"线程3");

t3.setPriority(Thread.MIN_PRIORITY);

t1.start();

t2.start();

t3.start();

}

}

我想让线程稳定的按照t1 t2 t3 的顺序执行 优先级并不能稳定的确定执行顺序  有没有更好的办法