Spring MVC, MessageConverters, Code Configuration Ignored

Question

I'm using a mix of xml and codebased configuration. One part of my code configuration was ignored. This one:

@Configuration
@EnableWebMvc
public class RestMvcConfig extends WebMvcConfigurerAdapter {

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        converters.add(converter());
        super.configureMessageConverters(converters);
    }

    @Bean
    public MappingJackson2HttpMessageConverter converter() {
        ObjectMapper mapper = new ObjectMapper();
        mapper.registerModule(new JodaModule());
        mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);

        MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
        converter.setObjectMapper(mapper);

        return converter;
    }
}

I debug the configureMessageConverters() method on startup of the Spring MVC app, and it is executed. Still, my JSON responses in the controllers are not converting Joda LocalDate into a String representation, but gives back the whole object structure.

Why is it ignored?

Answer 1

Using a combination of xml and code based configuration, it's easy to end up in a situation where you configure one thing twice, making Spring overwriting previous configurations. In my case, this was due to MVC also being configured in the xml:

<context:component-scan base-package="uk.co.imperatives.billing.rest" />
<mvc:annotation-driven />
<context:annotation-config />

So, in this case, the xml configuration resetted my code configuration. Removing the <mvc:annotation-driven /> fixed the problem. So, this worked:

<context:component-scan base-package="uk.co.imperatives.billing.rest" />
<context:annotation-config />