code: public SecurityController getSecurityController(String id) {
          SecurityController sc = (SecurityController) securityControllerMap.get( id );
          if( sc == null ) {
              // Try for a named bean
              try {
                  sc = applicationContext.getBean( id,
                      SecurityController.class );
              } catch( NoSuchBeanDefinitionException e ) {
                  // Try for a fallback
                  sc = getFallbackSecurityController();
              }
          }
          return sc;
      }
docs: Get the security controller for the given id. If the id is registered in our map,
  then return the registered controller. If not, then try to obtain a bean with the
  given id if it implements the SecurityController interface.
  @param id of controller to retrieve
  @return controller, null if not found