display prime numbers that are also square numbers

while (i <= 100) {
  j = 2;
  while (j <= (int) Math.sqrt(i)) {
    if (i % j == 0) break;
    // else
    j++;
  }
  if (j > (int) Math.sqrt(i)) {
    // i is prime
    if (Math.sqrt(i) % 1 == 0) {
      // i is square
      System.out.println(i);
    }
  }
  i++;
}