code: public String[] getRuleSetDisplayNames(ULocale loc) {
          String[] names = getNameListForLocale(loc);
          if (names != null) {
              return names.clone();
          }
          names = getRuleSetNames();
          for (int i = 0; i < names.length; ++i) {
              names[i] = names[i].substring(1);
          }
          return names;
      }
docs: Return the rule set display names for the provided locale.  These are in the same order
  as those returned by getRuleSetNames.  The locale is matched against the locales for
  which there is display name data, using normal fallback rules.  If no locale matches,
  the default display names are returned.  (These are the internal rule set names minus
  the leading '%'.)
  @return an array of the locales that have display name information
  @see #getRuleSetNames