Only one of my two receivers is receiving message from ActiveMQ Artemis multicast queue

I have two Spring Boot applications using JmsListener consuming from an ActiveMQ Artemis multicast queue named onboard_application and address named onboard_address but only one manages to receive the message and then the message gets deleted from the queue.

My listeners look like below snippet:

@JmsListener(destination = "onboard_address::onboard_application")
public void applicationOnboardingMessageReceiver(String message) throws JsonProcessingException {
    ApplicationDTO appDTO = objectMapper.readValue(message, ApplicationDTO.class);
    //Business logic
}

My message sender looks like:

public void sendMulticastMessage(String channel, Object payload) throws Exception {
    try {
        jmsTemplate.setPubSubDomain(true);
        jmsTemplate.convertAndSend(channel, objectMapper.writeValueAsString(payload));
    } catch (JsonProcessingException e) {
       //Take action
    } 
}

Configuration in application.yml:

spring:
 artemis:
   mode: native
   user: artemis
   password: artemis
   broker-url: tcp://localhost:61616
 jms:
   pub-sub-domain: true

Could you please suggest what am I missing or doing wrong? Thanks in advance.

Solution

What you're observing is the expected behavior since both JmsListener instances are configured to consume from a single queue (i.e. onboard_address::onboard_application - the fully qualified queue name). All the consumers on a particular queue share the messages on that queue.

If you want normal multicast (i.e. pub/sub) semantics then you should simply specify the name of the address, e.g.:

@JmsListener(destination = "onboard_address")

Use the same value for the application which sends the messages.

You can read more about the ActiveMQ Artemis address model in the documentation.