I'm trying to get used to how JSF works with regards to accessing data (coming from a spring background)

I'm creating a simple example that maintains a list of users, I have something like

<h:dataTable value="#{userListController.userList}" var="u">

Then the "controller" has something like

@Named(value = "userListController")
public class UserListController {
    private UserListService userListService;

    private List<User> userList;

    public List<User> getUserList() {
        userList = userListService.getUsers();
        return userList;

And the "service" (although it seems more like a DAO) has

public class UserListService {

    private EntityManager em;

    public List<User> getUsers() {
        Query query = em.createQuery("SELECT u from User as u");
        return query.getResultList();

Is this the correct way of doing things? Is my terminology right? The "service" feels more like a DAO? And the controller feels like it's doing some of the job of the service.


Is this the correct way of doing things?

Apart from performing business logic the inefficient way in a managed bean getter method, and using a too broad managed bean scope, it looks okay. If you move the service call from the getter method to a @PostConstruct method and use either @RequestScoped or @ViewScoped instead of @SessionScoped, it will look better.

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Is my terminology right?

It's okay. As long as you're consistent with it and the code is readable in a sensible way. Only your way of naming classes and variables is somewhat awkward (illogical and/or duplication). For instance, I personally would use users instead of userList, and use var="user" instead of var="u", and use id and name instead of userId and userName. Also, a "UserListService" sounds like it can only deal with lists of users instead of users in general. I'd rather use "UserService" so you can also use it for creating, updating and deleting users.

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The "service" feels more like a DAO?

It isn't exactly a DAO. Basically, JPA is the real DAO here. Previously, when JPA didn't exist, everyone homegrew DAO interfaces so that the service methods can keep using them even when the underlying implementation ("plain old" JDBC, or "good old" Hibernate, etc) changes. The real task of a service method is transparently managing transactions. This isn't the responsibility of the DAO.

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I can imagine that it does that in this relatively simple setup. However, the controller is in fact part of the frontend not the backend. The service is part of the backend which should be designed in such way that it's reusable across all different frontends, such as JSF, JAX-RS, "plain" JSP+Servlet, even Swing, etc. Moreover, the frontend-specific controller (also called "backing bean" or "presenter") allows you to deal in a frontend-specific way with success and/or exceptional outcomes, such as in JSF's case displaying a faces message in case of an exception thrown from a service.

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All in all, the correct approach would be like below:

<h:dataTable value="#{userBacking.users}" var="user">
@RequestScoped // Use @ViewScoped once you bring in ajax (e.g. CRUD)
public class UserBacking {

    private List<User> users;

    private UserService userService;

    public void init() {
        users = userService.listAll();

    public List<User> getUsers() {
        return users;

public class UserService {

    private EntityManager em;

    public List<User> listAll() {
        return em.createQuery("SELECT u FROM User u", User.class).getResultList();


You can find here a real world kickoff project here utilizing the canonical Java EE / JSF / CDI / EJB / JPA practices: Java EE kickoff app.

See also:

| improve this answer | |
  • "JPA is the real DAO here" gives my brain a deep impact to understand this statement. :) Is it anything that provides an abstraction to some kind of persistence mechanism like a DB and allows retrieval and persistence of domain objects to and from the DB without exposing the internal details of the underlying DB is said to be a DAO? This is somewhat confusing as compared to older questions/answers/blogs/tutorials/articles somewhere else. – Tiny Jun 28 '15 at 12:01
  • 2
    @Tiny: perhaps this answer is helpful to understand the original intent behind DAO pattern: stackoverflow.com/questions/7070467/dao-and-jdbc-relation – BalusC Jun 28 '15 at 12:06
  • @BalusC Why is Session Scope too broad? By using the view scope the list will have to be build every time the user loads the page, right? Isn't that "bad"? Or is it that we just prefer that, more than keeping the bean alive for the whole session and consuming memory? – LyK Sep 10 '15 at 8:32
  • @LyK: click "How to choose the right bean scope?" for explanation. – BalusC Sep 10 '15 at 8:51
  • 4
    @LyK: You shouldn't cache DB results in all sessions in the frontend. You should cache them in a single place in the backend. JPA offers 2nd level cache possibility. Additional advantage, it knows precisely when to invalidate a cached entity. – BalusC Sep 10 '15 at 9:00

It is a DAO, well actually a repository but don't worry about that difference too much, as it is accessing the database using the persistence context.

You should create a Service class, that wraps that method and is where the transactions are invoked.

Sometimes the service classes feel unnecessary, but when you have a service method that calls many DAO methods, their use is more warranted.

I normally end up just creating the service, even if it does feel unnecessary, to ensure the patterns stay the same and the DAO is never injected directly.

This adds an extra layer of abstraction making future refactoring more flexible.

| improve this answer | |
  • thanks, I'll probably just add that extra layer then. From a JSF perspective does what I'm doing look like the correct way to go? – PDStat Jun 4 '15 at 9:26
  • Looks fine, does it have to be session scoped - using sessions makes clustering somewhat more complex (but also commonly used). Not used jsf myself, I prefer anglular, vanilla html, and a rest api. – NimChimpsky Jun 4 '15 at 9:28
  • I'll be adding in some result pages saying things like 'user x added' or 'user x removed' so I assume so, not really sure yet just playing. – PDStat Jun 4 '15 at 9:31

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