I have the following code for a simple MqttClient using Spring…

package com.cbusha.be.component;

import com.hivemq.client.mqtt.MqttClient;
import com.hivemq.client.mqtt.MqttClientState;
import com.hivemq.client.mqtt.MqttGlobalPublishFilter;
import com.hivemq.client.mqtt.datatypes.MqttQos;
import com.hivemq.client.mqtt.mqtt3.Mqtt3AsyncClient;
import com.hivemq.client.mqtt.mqtt3.message.publish.Mqtt3Publish;
import jakarta.annotation.PostConstruct;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component
public class MqttClientComponent {

    private static final Logger logger = LoggerFactory.getLogger(MqttClientComponent.class);

    @Value("${mqtt.server.uri}")
    private String serverUri;

    @Value("${mqtt.client.id}")
    private String clientId;

    @Value("${mqtt.username}")
    private String username;

    @Value("${mqtt.password}")
    private String password;

    private Mqtt3AsyncClient mqttClient;

    @PostConstruct
    public void connect() {

        logger.info("Connecting to the MQTT server: {}", serverUri);

        mqttClient = MqttClient.builder()
                .useMqttVersion3()
                .identifier(clientId)
                .serverHost(serverUri.split(":")[1].substring(2))
                .serverPort(Integer.parseInt(serverUri.split(":")[2]))
                .buildAsync();

        mqttClient.connectWith()
                .simpleAuth()
                .username(username)
                .password(password.getBytes())
                .applySimpleAuth()
                .send()
                .whenComplete((connAck, throwable) -> {
                    if (throwable != null) {
                        logger.error("Error connecting to MQTT server", throwable);
                    } else {
                        logger.info("Connected to MQTT server: {}", serverUri);
                        subscribeToTopic();
                    }
                });
    }

    private void subscribeToTopic() {
        mqttClient.subscribeWith()
                .topicFilter("/zwave/Office/Big_Boy_Plug/lastActive")
                .qos(MqttQos.fromCode(0))
                .callback(this::handleMessage)
                .send()
                .whenComplete((subAck, throwable) -> {
                    if (throwable != null) {
                        logger.error("Error subscribing to topic", throwable);
                    } else {
                        logger.info("Subscribed to /zwave/Office/Big_Boy_Plug/lastActive");
                    }
                });
    }

    private void handleMessage(Mqtt3Publish publish) {
        logger.info("Message received on topic {}: {}", publish.getTopic(), new String(publish.getPayloadAsBytes()));
    }
}

And I have an MQTT client I am using to make sure it is publishing correctly

But I never see the Handle Message method get hit on the component. I do see the connection and subscribe success messages get called so I am not sure what I am missing.

My initial guess is it has something to do with the QOS. I am using HiveMQ and have Home Assistant on the other side. I set the QOS to 0 since I believe that should be the default.

I am using the lastActive because it is constantly updating.