Spring MVC LocaleChangeInterceptor annotation based doesn't work

import java.util.Locale;

import org.springframework.context.MessageSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.support.ReloadableResourceBundleMessageSource;
import org.springframework.web.servlet.HandlerMapping;
import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.i18n.CookieLocaleResolver;
import org.springframework.web.servlet.i18n.LocaleChangeInterceptor;
import org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping;

@Configuration
public class Config {
    @Bean
    public LocaleResolver localeResolver() {
        final CookieLocaleResolver ret = new CookieLocaleResolver();
        ret.setDefaultLocale(new Locale("en_US"));
        return ret;
    }

    @Bean
    public MessageSource messageSource() {
        final ReloadableResourceBundleMessageSource ret = new ReloadableResourceBundleMessageSource();
        ret.setBasename("classpath:lang");
        ret.setDefaultEncoding("UTF-8");
        return ret;
    }

    @Bean
    public HandlerMapping handlerMapping() {
        final LocaleChangeInterceptor interceptor = new LocaleChangeInterceptor();
        interceptor.setParamName("language");

        final DefaultAnnotationHandlerMapping ret = new DefaultAnnotationHandlerMapping();
        ret.setInterceptors(new Object[] { interceptor });
        return ret;
    }
}

The above is my annotation configuration. I've basically translated this tutorial's XML.

Strangely it doesn't work when I go to ...?language=fr.

However, the following does work (in app-servlet.xml) (notice here it's using locale):

<mvc:interceptors>
    <bean class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor">
        <property name="paramName" value="locale" />
    </bean>
</mvc:interceptors>

Another important thing to note is that when I put breakpoints on the above methods, all of the three of them, every breakpoint does break, which implies that "someone" is reading the values.

So, why wouldn't my annotation based interceptor doesn't work?