JAX-RS and CDI / @Provider and beans.xml

[superdev]

I made a simple project that make use of JAX-RS (RESTfull service)

I have a JAX-RS (RESTfull service) webservice project that deploys to JBoss 6.1. resteasy integrated with JSON is provided by JBoss 6.1 by default.  I wanted to change the date format of default JSON resource.

I got some help from the Internet and added a class extends JacksonJsonProvider:

http://stackoverflow.com/questions/8498413/accessing-jackson-object-mapper-in-resteasy

http://stackoverflow.com/questions/4428109/jersey-jackson-json-date-serialization-format-problem-how-to-change-the-form

@Provider
@Produces("application/json")
public class MyJacksonJsonProvider extends JacksonJsonProvider {
      public static final String pattern = "YYYY-MM-dd'T'HH:mm:ss";
     @Override
      public void writeTo(Object value, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String,Object> httpHeaders, OutputStream entityStream) throws IOException, WebApplicationException {
        ObjectMapper mapper = locateMapper(type, mediaType);
        // Set customized date format
        SimpleDateFormat sdf = new SimpleDateFormat(pattern);
        mapper.getSerializationConfig().setDateFormat(sdf);

        super.writeTo(value, type, genericType, annotations, mediaType, httpHeaders, entityStream);
    }
}

This works well until I added an empty beans.xml under WebContent/WEB-INF for CDI injection.

MyJacksonJsonProvider won't call, I still get default JSON date format.

Even I added the following dependency under pom.xml did not help.

<dependency>
          <groupId>org.jboss.resteasy</groupId>
          <artifactId>resteasy-jaxrs</artifactId>
      </dependency>
      <dependency>
          <groupId>org.jboss.resteasy</groupId>
          <artifactId>resteasy-cdi</artifactId>
          <version>2.2.1.GA</version>
      </dependency> 

Does anyone have any idea why "MyJacksonJsonProvider" will be ingnored if I have an empty beans.xml under "WebContent/WEB-INF" folder? Thanks a lot in advance!

FYI, this is the sample model class:

@XmlRootElement(name = "movie")
public class Movie {

    String name;
    String director;
    int year;
    Date date;

    @XmlElement
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @XmlElement
    public String getDirector() {
        return director;
    }

    public void setDirector(String director) {
        this.director = director;
    }

    @XmlAttribute
    public int getYear() {
        return year;
    }

    public void setYear(int year) {
        this.year = year;
    }

    @XmlElement
    public Date getDate() {
        return date;
    }

    public void setDate(Date date) {
        this.date = date;
    }

}

And this is the class that produces JSON resource:

@Path("/json/movie")
public class JSONService {

    @GET
    @Path("/get")
    @Produces("application/json")
    public Movie getMovieInJSON() {

        Movie movie = new Movie();
        movie.setName("Little flower");
        movie.setDirector("Zhang Zheng");
        movie.setYear(1979);
        movie.setDate(new Date());

        return movie; 

    }
}