public boolean only14(int[] nums) {
  for (int n : nums) {
     if (!(1 == n || 4 == n)) {
       return false;
     }
  }
  return true;
}

public boolean only14(int[] nums) {
  for (int n : nums) {
     if (1 != n && 4 != n) {
       return false;
     }
  }
  return true;
}