Apache cxf delete request error

Im trying to use @DELETE request after a made some simple web application which ive tested using soapui. With this application i can add and get users/book to data base. Now im trying to made e @DELETE request but i cant make it. Here is the code:

//UserServiceImpl

@PersistenceContext
private EntityManager em;

@Override
public void deleteUser(Long id) {
    if (null == id || id.longValue() < 1) {
        throw new IllegalArgumentException(" User id can not be null or less than zero. ");
    }

    User u = em.find(User.class, id);
    em.remove(u);

}

//UserResource

@Autowired
private UserService userService;

@DELETE
@Path("/delete/{id}")
public Response deleteUser(@PathParam("id") String id) {
    Response response;
    try {
        User user = userService.deleteUser(Long.valueOf(id));//here is the error
        if (user != null) {
            response = Response.status(HttpServletResponse.SC_OK).entity(user).build();
        } else {
            response = Response.status(HttpServletResponse.SC_NOT_FOUND).build();
        }
    } catch (IllegalArgumentException e) {
        response = Response.status(HttpServletResponse.SC_NOT_FOUND).build();
    }
    return response;
}