JacksonConfig.java

@Configuration
public class JacksonConfig {

    //TODO: Autoscan
    final static Map<Class<?>, Class<?>> mixins = ImmutableMap.<Class<?>, Class<?>>builder()
            .put(..., ...)
            .build();

    @Autowired
    EntityManagerFactory emf;

    @Autowired
    RequestMappingHandlerAdapter requestMappingHandlerAdapter;

    @PostConstruct
    public void init() {
        SessionFactory sessionFactory = emf.unwrap(SessionFactory.class);
        Hibernate4Module module = new Hibernate4Module(sessionFactory)
                .enable(Hibernate4Module.Feature.FORCE_LAZY_LOADING)
                .disable(Hibernate4Module.Feature.USE_TRANSIENT_ANNOTATION);

        List<HttpMessageConverter<?>> messageConverters = requestMappingHandlerAdapter.getMessageConverters();
        final MappingJackson2HttpMessageConverter mc = getJacksonMessageConverter(messageConverters);
        mc.getObjectMapper().setMixIns(mixins).registerModule(module);
    }

    static MappingJackson2HttpMessageConverter getJacksonMessageConverter(
            final List<HttpMessageConverter<?>> converters) {

        for (final HttpMessageConverter<?> converter : converters) {
            if (converter instanceof MappingJackson2HttpMessageConverter) {
                return (MappingJackson2HttpMessageConverter) converter;
            }
        }

        return null;
    }
}