java使用多线程找出最大随机数

public class four2 {
 static long AllMax=-1;
 public static void main(String[] args) {
 // TODO Auto-generated method stub
 MyThr t1=new MyThr();
 MyThr t2=new MyThr();
 MyThr t3=new MyThr();
 MyThr t4=new MyThr();
 MyThr t5=new MyThr();
 t1.start();
 t2.start();
 t3.start();
 t4.start();
 t5.start();
 
 try {
  t1.join();
  t2.join();
  t3.join();
  t4.join();
  t5.join();
 } catch (InterruptedException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
 }
 System.out.println("10000个数中的最大值为："+AllMax);
 }
 
 public static class MyThr extends Thread{
 public void run(){
  long rand;
  for(int i=1;i<=2000;i++){
  rand=(long)(Math.random()*100000)%100000;
  //System.out.println(rand);
  if(rand>AllMax){
   AllMax=rand;
  }
  }
 }
 } 
}