code: public static String[] toArrayElement(String s) {
      return (s == null || s.length() == 0) ? new String[0] : new String[]{s};
    }
docs: Takes a String s and returns a new String[1] with s as the only element.
  If s is null or "", return String[0].
  
  @param s The element to be wrapped
  @return String[]