code: protected void addAccessControl(AccessControl accessControl) {
  
      String id = accessControl.getId();
      AccessControl existing = this.id2nodeMap.get(id);
      if (existing == null) {
        this.id2nodeMap.put(id, accessControl);
        LOG.debug("Registered access control {}", accessControl);
      } else if (existing == accessControl) {
        LOG.debug("Access control {} was already registered.", accessControl);
      } else {
        throw new IllegalStateException("Duplicate access control with ID '" + id + "'.");
      }
    }
docs: Registers the given {@link AccessControl} and may be used for configuration of access controls during
  bootstrapping. This method should not be used after the application startup (bootstrapping) has completed.
  
  @param accessControl the {@link AccessControl} to register.