code: public NumberFormat getNumberFormat(char field) {
          Character ovrField;
          ovrField = Character.valueOf(field);
          if (overrideMap != null && overrideMap.containsKey(ovrField)) {
              String nsName = overrideMap.get(ovrField).toString();
              NumberFormat nf = numberFormatters.get(nsName);
              return nf;
          } else {
              return numberFormat;
          }
      }
docs: give the NumberFormat used for the field like 'y'(year) and 'M'(year)
  
  @param field the field the user wants
  @return override NumberFormat used for the field