code: public ULocale getFallback() {
          if (localeID.length() == 0 || localeID.charAt(0) == '@') {
              return null;
          }
          return new ULocale(getFallbackString(localeID), (Locale)null);
      }
docs: <strong>[icu]</strong> Returns the fallback locale for this locale.  If this locale is root,
  returns null.