code: private RegistrationEntryList getRegistrationEntryList(String subject, RelatedFinder finder)
      {
          RegistrationEntryList registrationEntryList;
          RegistrationKey key = new RegistrationKey(subject, finder.getFinderClassName());
          if (logger.isDebugEnabled())
          {
              logger.debug("**************Adding application notification registration with key:  " + key.toString());
          }
          registrationEntryList = mithraApplicationNotificationSubscriber.get(key);
          if (registrationEntryList == null)
          {
              registrationEntryList = new RegistrationEntryList();
              mithraApplicationNotificationSubscriber.put(key, registrationEntryList);
          }
          return registrationEntryList;
      }
docs: Must only be called from the thread which is used for registration