public class Test {

  public static boolean isPrime(int n) {
      for (int i = 2; i <= Math.sqrt(n); i++) // check possible factors
      {
        if (n % i == 0) { // i is a factor
          return false; // so n is not prime
        }
      }
    return true; // no factors so it is prime
  }

  public static void main(String[] args) {
for (int i=2; i<100; i++) // test - all primes less than 100
      if (isPrime(i)) System.out.println(i);
  }
}