code: public void publish(String subtopic, Object data) {
      try {
        MqttConnection.publish(settingsController.getMqttSettings(), subtopic, data);
      } catch (JsonProcessingException | MqttException e) {
        logger.error("Failed to publish MQTT message", e);
      }
    }
docs: Publishes data as JSON string into given topic
  
  @param settings MQTT settings
  @param subtopic subtopic to deliver the message to.
  @param data data to be send