code: private void initializeMapper() {
      if (valueClass == null) {
        valueMapper = CatchAllMapper.getInstance();
      } else {
        try {
          valueMapper = MapperFactory.getInstance().getMapper(valueClass);
        } catch (NoSuitableMapperException exp) {
          valueMapper = CatchAllMapper.getInstance();
        }
  
      }
    }
docs: Initializes the mapper for values in the Map.