code: public static String formatMessage(TraceComponent tc, Locale locale, String msgKey, Object... objs) {
          return formatMessage(tc, (locale == null) ? null : Collections.singletonList(locale), msgKey, objs);
      }
docs: Like {@link #formatMessage(TraceComponent, List, String, Object...)},
  but takes a single Locale.
  
  @see #formatMessage(TraceComponent, List, String, Object...)