How to find Prime number in java ??

package org.cmania;

public class PrimeTime
{
    public static void main(String[] args)
{
          int n=11;
              System.out.println(isPrimeNumber(n)? n+" is prime number." : n+" is not prime number.");               n=12;
             System.out.println(isPrimeNumber(n)? n+" is prime number." : n+" is not prime number.");               n=13;
             System.out.println(isPrimeNumber(n)? n+" is prime number." : n+" is not prime number.");               n=14;
             System.out.println(isPrimeNumber(n)? n+" is prime number." : n+" is not prime number.");
        }

          /** * returns true if number is prime using ternary operator. */


         public static boolean isPrimeNumber(int n)
           {
                for(int i=2;i<=Math.sqrt(n);i++)
                  {
                      if(n%i==0)
                       {
                            return false;
                        }
                   }
                return true; //means number wasn't divisible by any of the number, it's a prime number.
           }
 }