We are using a JpaEventStorageEngine with various EventProcessors in a spring context.
Initally Axon complained about a missing eventBus bean so we added a SimpleEventBus to our configuration.
On startup Axon now finds 2 eventBus beans and states it will use the eventStore bean, not the eventBus bean.
So Axon requires an eventBus on startup but won't use it. In debug mode I can see all our EventProcessors are subscribed to both the eventStore as well as the eventBus.
What is that SimpleEventBus used for?