docs: @Override
      public void addObserver(Observer observer) {
          super.addObserver(observer);
          if (countObservers() > 1) {
              super.deleteObserver(observer);
              AbstractConnectionFactoryService cfSvc = (AbstractConnectionFactoryService) observer;
              Object[] params = new Object[] { CONNECTION_MANAGER, name, cfSvc.getConfigElementName() };
              RuntimeException failure = connectorSvc.ignoreWarnOrFail(tc, null, UnsupportedOperationException.class, "CARDINALITY_ERROR_J2CA8040", params);
              if (failure != null)
                  throw failure;
          }
      }