Errors when adding users into a class in Play Jongo Java?

I’m beginner with Play Jongo Java…I am doing: adding users into to a class…but it is errors….I repaired and more wrong:

views.’lophoc.scala.html’:

 @helper.form(routes.Application.addUser(), 'class -> "form-signin" ) { 
      <input type="text" name="hdh" value="He Dieu Hanh" autofocus>
      <button  type= "submit"  > Insert </button> 
}

controller.Application.java:

public class Application extends Controller {

@Inject private UserDAO userDao;
@Inject private LophocDAO lophocDAO;
@Inject private FormFactory formFactory;

public Result addUser(){
    DynamicForm requestData = formFactory.form().bindFromRequest();
    String lophoc = requestData.get("hdh");
    if(Secured.isMemberOf(lophoc)){
        lophocDAO.addMember(
            lophoc, 
            requestData.get("email")
        );
        return  redirect(routes.Application.index());       
    }

    return redirect(routes.Application.lophoc());
}
}

controllers.Secured.java:

 public class Secured extends Security.Authenticator {

    @Override
    public String getUsername(Context ctx) {
        return ctx.session().get("email");
    }
    public static boolean isMemberOf(String lophoc){
        return LophocDAO.isMember(
            lophoc,
            Context.current().request().username()
        );  
    }
}

dbaccess.LophocDAO.java:…I wrong at addUser()…I found Jongo but I don’t understand about save() method.

public class LophocDAO{

    private MongoCollection lophocCollectionAccess;

    public LophocDAO() {
            lophocCollectionAccess = DBAccessProvider.getInstance().getCollection("lophoc");
        }

         public boolean isMember(String tenlop, String user){
                MongoCursor<Lophoc> cursor = lophocCollectionAccess.find("{tenlop:#,member.email:#}",tenlop,user).as(Lophoc.class);
                return cursor.count() > 0;
            }

        public User addMember(String tenlop, String user){

                Lophoc lop = lophocCollectionAccess.save("{member.email:#}",user).as(Lophoc.class);         
            }

models.Lophoc.java:

    public class Lophoc {

    @MongoId
    @MongoObjectId
    private String lopId;
    private String malop;
    private String tenlop;
    private String siso;
    private String giangvien;

    public List<User> members = new ArrayList<User>();

    public Lophoc(){
        members = new ArrayList<String>();
    }

    public Lophoc(String lopId,String malop,String tenlop,String siso,String giangvien){
        this.lopId=lopId;
        this.malop=malop;
        this.tenlop=tenlop;
        this.siso=siso;
        this.giangvien=giangvien;
        members = new ArrayList<String>();
    }
--getter and setter--