When using the ClusteringEventBus, you provide names to each event handler Cluster. With the AMQP connector, each cluster listens to a queue. When two listeners listen to the same queue, each message is only processed by one of them. You can also set up clusters to connect in ‘exclusive mode’, which causes only one cluster instance at a time to read from the queue. When it disconnects, the other cluster with the same name (on another host) can take over.
All this is not important unless you’re in a distributed setup. With a ‘simple’ or local setup, dispatching always happens locally.