@Path("/xml/users")
public class XMLService {

    @GET
    @Path("{id}")
    @Produces(MediaType.APPLICATION_XML)
    public UserDTO getUser(@PathParam("id") long id) {
        UserDTO dto = new UserDTO();
        dto.setId(id);
        dto.setName("_name" + id);
        dto.setSurname("_surname" + id);
        return dto;
    }

    @POST
    @Consumes(MediaType.APPLICATION_XML)
    public Response addUser(UserDTO user) {
        System.out.println("1111");
        return Response.ok().build();
    }

}

@XmlRootElement(name = "user")
@XmlAccessorType(value = XmlAccessType.NONE)
public class UserDTO implements Serializable {

    @XmlElement
    protected String name;

    @XmlElement
    protected String surname;

    @XmlAttribute
    protected long id;
    
    getters setters toString...
}

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<user id="1">
    <name>_name1</name>
    <surname>_surname1</surname>
</user>