@Override
protected List<HttpMessageConverter<?>> getMessageConverters() {
MappingJackson2HttpMessageConverter jsonConverter = new MappingJackson2HttpMessageConverter();
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.configure(FAIL_ON_UNKNOWN_PROPERTIES, false);
objectMapper.configure(WRITE_DATES_AS_TIMESTAMPS, false);
objectMapper.configure(FAIL_ON_EMPTY_BEANS, false);
objectMapper.setSerializationInclusion(NON_NULL);
jsonConverter.setObjectMapper(objectMapper);
FormHttpMessageConverter formHttpMessageConverter = new FormHttpMessageConverter();
formHttpMessageConverter.addPartConverter(jsonConverter);