Unable to reference the osgi service into a servlet

I am trying to reference a service into a servlet,but when I use @Refernce annotation i am getting 404 not found exception even though my service is registered properly.

here is my code snippet

Note: I am using OSGI R6 Annotations in AEM 6.2

Servlet:

--------

@Component(immediate = true,

        service = Servlet.class,

        property = {

                "sling.servlet.paths=/express/bin/getDynamicData",

                "sling.servlet.extensions=json",

                "sling.servlet.methods=GET"

        }

)

@Designate(ocd=DynamicDataServlet.Configuration.class)

public class DynamicDataServlet extends SlingSafeMethodsServlet {

     @Reference

     private DynamicDataService dynamicService;

@Override

    protected void doGet(final SlingHttpServletRequest request,

    final SlingHttpServletResponse response) throws ServletException, IOException {

          ------------

          -------------

          dynamicService.getData(resourceResolver, region) ;

}

}

Service interface:

-------------------

public interface DynamicDataService {

  JSONObject getDynamicData(ResourceResolver resourceResolver, String region);

}

ServiceImpl:

----------------

@Component

(service = DynamicDataService.class, name = "TNT Dynamic Data Service", immediate =true)

public class DynamicDataServiceImpl implements DynamicDataService {

@Override

  public JSONObject getDynamicData(ResourceResolver resourceResolver, String region) {

     --------

     --------

     -------

}

}