KafkaAdmin - see Configuring Topics

ProducerFactory - see Sending Messages

ConsumerFactory - see Receiving Messages

Starting with version 2.5, each of these extends KafkaResourceFactory. This allows changing the bootstrap servers at runtime by adding a Supplier to their configuration: setBootstrapServersSupplier(() → …​). This will be called for all new connections to get the list of servers. Consumers and Producers are generally long-lived. To close existing Producers, call reset() on the DefaultKafkaProducerFactory. To close existing Consumers, call stop() (and then start()) on the KafkaListenerEndpointRegistry and/or stop() and start() on any other listener container beans.

For convenience, the framework also provides an ABSwitchCluster which supports two sets of bootstrap servers; one of which is active at any time. Configure the ABSwitchCluster and add it to the producer and consumer factories, and the KafkaAdmin, by calling setBootstrapServersSupplier(). When you want to switch, call primary() or secondary() and call reset() on the producer factory to establish new connection(s); for consumers, stop() and start() all listener containers. When using @KafkaListener s, stop() and start() the KafkaListenerEndpointRegistry bean.

https://www.javaguides.net/2022/12/spring-boot-apache-kafka-tutorial-16.html