WAP to check no. is prime/not

/*WAP to check no. is prime/not*/

import java.lang.*;

class prime
   {
    int num,count;
    prime(int num1)
      {
       num=num1;
       count=0;
      }
    void calculate_prime()
      {
       for(int i=1;i        {
         if(num%i==0)
         count++;
         if(count>2)
         break;
        }
      }
   void display()
     {
      if(count>2)
      System.out.println("not prime " + num);
      else
      System.out.println("prime " + num);
     }
   }


class demo_prime
   {
    public static void main(String arg[])
      {
       prime p1=new prime(5);
       prime p2=new prime(21);

       p1.calculate_prime();
       p1.display();

       p2.calculate_prime();
       p2.display();
      }
   }