I have just managed to look into this issue. It appears that you get the NullPointerException, because Axon cannot resolve the SomeBean parameter. Although it should not lead to a NPE (but a more descriptive exception), there is a mistake in your code. You need to tell Axon to look for Spring beans as candidates for parameter injection.
The easiest way to do so, is by adding @AnnotationDriven to your Spring @Configuration. Then, on the @Bean methods that create the AggregateAnnotationCommandHandler and EventSourcingRepository, pass a parameter ParameterResolverFactory. The @AnnotationDriven will make sure an appropriate instance is created.
I have just adapted the quickstart sample to show how to do this:
Note that proper Spring support is work under construction. Soon, the @AnnotationDriven will allow you to annotated your aggregate using @AggregateRoot and all the Spring wiring is automatic…