code: public void register(Authenticator authenticator) {
  		if (this.authenticator == null) {
  			this.authenticator = authenticator;
  		} else if (!authenticator.getClass().getSimpleName().equals(this.authenticator.getClass().getSimpleName())) {
  			throw new ConfigurationException("attempt to replace authenticator " +
  					this.authenticator.getClass().getSimpleName() + " by " +
  					authenticator.getClass().getSimpleName());
  		}
  	}
docs: Used to register any first available authenticator within cluster.
  
  @param authenticator