AxonConfig.java

@Configuration
@Import(CassandraTestConfig.class)
public class AxonTestContext {

	@Bean
	public EventStorageEngine eventStorageEngine(Cluster cluster){
		return new CassandraEventStorageEngine(cluster, new XStreamSerializer());
	}

	@Bean
	public EventStore eventStore(EventStorageEngine eventStorageEngine){
		return new AbstractEventStore(eventStorageEngine) {
			@Override
			public TrackingEventStream streamEvents(TrackingToken trackingToken) {
				return null;
			}
		};
	}

	@Bean
	public EventSourcingRepository<TestAggregate> aggregateEventSourcingRepository(EventStore eventStore){
		return new EventSourcingRepository<>(TestAggregate.class, eventStore);
	}

	@Bean
	public CommandBus commandBus(){
		CommandBus commandBus = new AsynchronousCommandBus();
		AnnotationCommandHandlerAdapter annotationCommandHandlerAdapter = new AnnotationCommandHandlerAdapter(
			new TestAggregate()
		);
		commandBus.subscribe(TestAggregateCreateCommand.class.getName(), annotationCommandHandlerAdapter);
		commandBus.subscribe(TestAggregateNameChangeCommand.class.getName(), annotationCommandHandlerAdapter);
		return commandBus;
	}
}

TestAggregate.java

@NoArgsConstructor
public class TestAggregate {

	@AggregateIdentifier private UUID someAggregateId;
	private String name;

	@CommandHandler
	public TestAggregate(TestAggregateCreateCommand testAggregateCreateCommand){
		apply(new TestAggregateCreatedEvent(testAggregateCreateCommand.getTestAggregateId()));
	}

	@CommandHandler
	public void setName(TestAggregateNameChangeCommand testAggregateNameChangeCommand){
		apply(new TestAggregateNameChangedEvent(
			testAggregateNameChangeCommand.getTestAggregateId(),
			testAggregateNameChangeCommand.getName()
		));
	}

	@EventSourcingHandler
	public void on(TestAggregateCreatedEvent createdEvent){
		this.someAggregateId = createdEvent.getSomeAggregateId();
	}

	@EventSourcingHandler
	public void on(TestAggregateNameChangedEvent testAggregateNameChangedEvent){
		this.name = testAggregateNameChangedEvent.getName();
	}
}

Check out the method: AnnotationCommandHandlerAdapter.subscribe(). It will automatically subscribe itself as the handler for all known Command types.