code: public static BtcFormat getMicroInstance(int scale, int... groups) {
          return getInstance(MICROCOIN_SCALE, defaultLocale(), scale, boxAsList(groups));
      }
docs: Return a new microcoin-denominated formatter with the specified fractional decimal
  placing.  The returned object will format and parse values according to the default
  locale, and will format the fractional part of numbers with the given minimum number of
  fractional decimal places.  Optionally, repeating integer arguments can be passed, each
  indicating the size of an additional group of fractional decimal places to be used as
  necessary to avoid rounding, to a limiting precision of satoshis.