code: public static String upperCaseInternal(String s) {
          if (isNullOrEmpty(s)) {
              return s;
          }
          return s.toUpperCase(LOCALE_INTERNAL);
      }
docs: HC specific settings, operands etc. use this method.
  Creates an uppercase string from the given string.
  
  @param s the given string
  @return an uppercase string, or {@code null}/empty if the string is {@code null}/empty