code: private void init() {
          // null implies "no expression"
          value_ = type_ = pattern_ = null;
          currencyCode_ = currencySymbol_ = null;
          groupingUsed_ = null;
          maxIntegerDigits_ = minIntegerDigits_ = null;
          maxFractionDigits_ = minFractionDigits_ = null;
      }
docs: (re)initializes state (during release() or construction)