code: public static AsyncWebResource getAnnisAsyncWebResource()
    {
      // get URI used by the application
      String uri = (String) VaadinSession.getCurrent().getAttribute(
        KEY_WEB_SERVICE_URL);
  
      // if already authentificated the REST client is set as the "user" property
      AnnisUser user = getUser();
  
      return getAnnisAsyncWebResource(uri, user);
    }
docs: Gets or creates an asynchronous web resource to the ANNIS service.
  
  This is a convenience wrapper to {@link #getAnnisWebResource(java.lang.String, annis.security.AnnisUser)
  }
  that does not need any arguments
  
  @return A reference to the ANNIS service root resource.