Primality in Hex!

package is_prime.is_prime;public class is_prime {  public static void main(String arg[]) {          long start = System.currentTimeMillis(), end;          boolean is_prime = false;          boolean done_increase=false;          for (int i = 1; i > 0; i++) {                  is_prime = is_prime(i);                  if (is_prime) System.out.println(Integer.toString(i,16));          }          end = System.currentTimeMillis();          long total = end - start;          System.out.println(Long.toString(total,16));  }  public static boolean is_prime(int check_prime) {          if(check_prime < 4) return true;          if(check_prime % 2 == 0 || check_prime % 3 == 0) return false;          for(int i = 1, j = 5; j <= (int)(Math.sqrt(check_prime)); i ++, j = (6*j-1)) {                  if(check_prime % j == 0) return false;                  j += 2;                  if(check_prime % j == 0) return false;          }          return true;  }}