code: public Calendar retrieveCalendar(String name, T jedis) throws JobPersistenceException{
          final String calendarHashKey = redisSchema.calendarHashKey(name);
          Calendar calendar;
          try{
              final Map<String, String> calendarMap = jedis.hgetAll(calendarHashKey);
              if(calendarMap == null || calendarMap.isEmpty()){
                  return null;
              }
              final Class<?> calendarClass = Class.forName(calendarMap.get(CALENDAR_CLASS));
              calendar = (Calendar) mapper.readValue(calendarMap.get(CALENDAR_JSON), calendarClass);
          } catch (ClassNotFoundException e) {
              logger.error("Class not found for calendar " + name);
              throw new JobPersistenceException(e.getMessage(), e);
          } catch (IOException e) {
              logger.error("Unable to deserialize calendar json for calendar " + name);
              throw new JobPersistenceException(e.getMessage(), e);
          }
          return  calendar;
      }
docs: Retrieve a calendar
  @param name the name of the calendar to be retrieved
  @param jedis a thread-safe Redis connection
  @return the desired calendar if it exists; null otherwise