Java: Message Brokers (Kafka)

Kafka ensures messages are stored safely even if consumers are offline, allowing for eventual processing.

Kafka retains messages in a durable log on disk until they are consumed. This means if a consumer service is down, it can retrieve all missed messages once back online. For instance, if the shipping service in an e-commerce system is temporarily down during a sale, it won't miss any order events as Kafka retains them.