code: public void eventUnreferenced(ActivityHandle arg0, FireableEventType fireableEventType,
              Object event, Address address, ReceivableService receivableService, int integer) {
          // release event thread
          releaseHttpRequest((HttpServletRequestEvent) event);
      }
docs: /*
  /*
  (non-Javadoc)
  
  @see javax.slee.resource.ResourceAdaptor#eventUnreferenced(javax.slee.resource.ActivityHandle,
  javax.slee.resource.FireableEventType, java.lang.Object, javax.slee.Address,
  javax.slee.resource.ReceivableService, int)