4 digit Random Number generation in java.

import java.util.*;
public class test {
   public static void main(String[] args) {
   creating UUID      
   UUID uid = new UUID();     
   HashSet hs=new HashSet();
     
   // checking the value of random UUID

  for(int i=1;i<1000;i++){
   //System.out.println("Random UUID value: "+UUID.randomUUID().toString());   
    
    Random r=new Random();
    String st[]=new Integer(r.nextInt(i)).toString().split("");
   String s[]=UUID.randomUUID().toString().split("-");
   System.out.println(UUID.randomUUID());
   System.out.println(s[1].replaceAll("[^0-9]","1"+st[0])); 
   hs.add(s[1].replaceAll("[^0-9]","1"+st[0]));
  
   }
       
  System.out.println(hs.size()+".............................");
}
}