Unlike JMS consumers, Kafka consumers need group id. Why? Let's start the analysis from JMS consumers. JMS supports both queue and topic as follows, point-to-point queue with multiple consumers, each of which receives a subset of the messages in the queue. publisher subscriber topic with multiple consumers, each of which receives a full copy of all the messages in the topic. JMS queue obviously has the advantage of load balancing in message consumption, while a topic has the advantage of supporting multiple subscribers. Now the question is how we combine JMS queue and topic into a single message model(without a separate queue and topic) with the advantage of both load balancing and multiple subscribers. With the introduction of group id , this objective is achieved in kafka. Specifically, a kafka consumer group is composed of one or more consumers with the same group id , and each consumes a subset of the messages based on kafka topic partition. Moreover...