code: @Deprecated
      protected StringBuffer applyRules(final Calendar calendar, final StringBuffer buf) {
          return (StringBuffer) applyRules(calendar, (Appendable) buf);
      }
docs: Performs the formatting by applying the rules to the
  specified calendar.
  
  @param calendar the calendar to format
  @param buf      the buffer to format into
  @return the specified string buffer
  @deprecated use {@link #format(Calendar)} or {@link #format(Calendar, Appendable)}