在java中可有两种方式实现多线程，一种是继承Thread类，一种是实现Runnable接口

//继承thread类
class PrimeThread extends Thread{
long minPrime;
PrimeThread(long minPrime)
{
this.minPrime=minPrime;
}
public void run(){
//computer primes larger than minPrime
}
}
//调用方法
PrimeThread p=new PrimeThread(143);
p.start();

//调用Runnable接口
class PrimeRun implements Runnable{
long minPrime;
PrimeRun(long minPrime){
this.minPrime=minPrime;
}
public void run(){
//compuyer primes larger than minPrime
}
}
//调用方法
PrimeRun p=new PrimeRun(143);
new Thread(p).start();