code: private static Date parseDate(@SuppressWarnings("SameParameterValue") String stringDate)
      {
          try {
              return formatter.parse(stringDate);
          } catch (ParseException e) {
              e.printStackTrace();
              return null;
          }
      }
docs: Helper method used to parse a date in string format.  Meant to encapsulate the error handling.
  
  @param stringDate  String in format of MM-dd-yyyy
  @return Date key