OO vs. Layered; balancing “OO purity” with getting things done

class UserServlet {
  handleRequest() {
    String id = request.get("id");
    String name = request.get("name");
    if (UserBizLayer.updateUserName(id,name))
      response.setStatus(OK);
    else
      response.setStatus(BAD_REQUEST);
  }
}

class UseBizLayer {
    updateUserName(String id, String name) {
        long key = toLong(id);
        user = userDAO.find(key);
        if user == null
            return false;
        if (!validateUserName(name))
            return false;
        user.setName(name);
        userDAO.update(user);
        return true;
    }

    validateUserName(String name) {
        // do some validations and return
    }
}

class User {
    long key;
    String name;
    String email;

    // imagine getters/setters here
}

public class UserModel extends DatabaseModel implements XMLable, CRUDdy, Serializable, Fooable, Barloney, Baznatchy, Wibbling, Validating {
  // member fields
  // getters and setters
  // 100 interface methods
}