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Re: [jakarta.ee-community] EJB -> CDI migration (was Re: Defining Jakarta EE 12 Scope in Program Plan)

Hi all,

I completely agree with that. EJBs are not bad per se and should not be abandoned.
Everyone is free to use them or not.

Best regards,

Bernd


Am 28.10.24 um 14:54 schrieb Ralph Soika via jakarta.ee-community:
Hello,

I became aware of this discussion through the topic "EJB -> CDI migration" and would like to briefly share my thoughts about it.
My fear here is to "ban" EJBs as something outdated, complicated and unnecessary. But is that right?
I myself run with imixs.org <https://www.imixs.org> a very large Jakarta EE project. And my opinion is that you should always implement the DataAccessLayer as also complex ProcessingServices in a stateless EJB in order to make use of the transaction capability.
I do know that you can also use CDI for data access. But is it the same?

For example in my own project (a BPMN workflow engine) the DataAccess Service as also the Engine itself is implemented as a stateless EJB. A project that is using the library just need to inject the WorkflowEngine. The user does not have to think about transactions or EJBs at this moment. The app developer can now extend the engine behavior by implementing so called 'Plug-Ins' as simple CDI beans. Such a CDI bean is a kind of adapter class that can for example react on specific CDI Events in the processing life-cycle. And of course the developer can again inject the DataService form the Workflow Engine to create new data.

The point is that if something goes totally wrong, the default transaction manager takes care about the rollback over all layers.

And this all comes for free just because of using the stateless local EJB pattern. For the developer there is no need to think about EJBs at all.

I may be wrong here, but I would always advise a developer to implement the data access layer via EJBs to keep the rest of the application as lean as possible.
Therefore, in my opinion, EJBs play an important role. A tutorial should not hide its  concepts.

Best regards

Ralph

On 28.10.24 14:21, Reza Rahman via jakarta.ee-community wrote:
I think the Tutorial refactoring work could easily be tagged “good first issue” and “help wanted”. We have a shockingly low number of those across EE4J projects.
----------------------------------------------------------------------------------------------------
*From:* Kito Mann <kito.mann@xxxxxxxxxxx>
*Sent:* Sunday, October 27, 2024 11:50 PM
*To:* jakarta.ee-spec@xxxxxxxxxxx <jakarta.ee-spec@xxxxxxxxxxx>; Jakarta EE community discussions <jakarta.ee-community@xxxxxxxxxxx>; jakarta.ee-marketing@xxxxxxxxxxx <jakarta.ee- marketing@xxxxxxxxxxx>; Reza Rahman <reza_rahman@xxxxxxxx> *Cc:* Jakarta EE Ambassadors <jakartaee-ambassadors@xxxxxxxxxxxxxxxx>; juneau001@xxxxxxxxx <juneau001@xxxxxxxxx>; Kito Mann <kito.mann@xxxxxxxxxx>
*Subject:* Re: EJB -> CDI migration (was Re: Defining Jakarta EE 12 Scope in Program Plan)
I love all three of these ideas:

 1. EJB -> CDI Migration Guide
 2. New EJB -> CDI Migration talk
 3. Updating the Jakarta EE Tutorial to remove EJB when possible

(3) is non-trivial since a lot of work needs to be done upgrading/rewriting the examples in general, but that doesn’t mean I can’t at least break that work down into the issue tracker. Also, the intro (which I rewrote) specifically does not mention EJB.

I’d like to add another: Writing an OpenRewrite  for migrating from EJB->CDI.

___

Kito D. Mann <https://kitomann.com> | @kito99@mastodon.social <https://mastodon.social/@kito99>| LinkedIn <https://www.linkedin.com/in/kitomann/>
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On Oct 27, 2024 at 2:46 PM -0400, Reza Rahman <reza_rahman@xxxxxxxx>, wrote:

    I am moving comments on my Jakarta EE 12 Google Doc
    (https://docs.google.com/document/d/1U2qEqF9K969t5b3YuX4cwex5LJPvF3bt1w27cdKNpDM/edit?usp=sharing)
    to Jakarta EE mailing lists when possible. The problem with Google Docs
    comments is that they do not scale very well, aren't very readable on
    smaller devices, and do not archive well. I will do so one email per
    comment. The person commenting is copied.

    Context: Why does replacing EJB matter?

    Josh Juneau (Community): Are there any comprehensive tutorials on how to
    utilize CDI rather than EJB for querying entities? It seems like these
    tutorials need to be made front and center in an effort to help steer
    people to CDI and to show that EJB is no longer needed in many cases.

    Reza Rahman (Microsoft): Good point. As of Jakarta EE 11, it is indeed
    possible to just use CDI now for basic CRUD in a transactional and
    thread safe manner with Jakarta Persistence. The same for EJB
    @Asynchronous and @Schedule. At the bare minimum, this is worthy of an
    Eclipse Foundation newsletter article and/or JakartaOne talk. The
    material could cover where EJB is not needed any more and where it is
    still needed. The title could be something attention grabbing like -
    "EJB is Dead, Long-Live CDI and Jakarta EE". We could also ensure a
    revised Jakarta EE 11 Tutorial can avoid using EJB when possible. Maybe
    Kito could comment on this? Additionally, the Marketing Committee has
    been sponsoring some guides. Could we consider already starting an EJB
    migration guide?

    On 10/22/2024 5:30 AM, Reza Rahman wrote:

        Hi folks,

        I would like to see if we can define clear, compelling, and specific
        scope for Jakarta EE 12 as part of the Steering Committee Program
        Plan:
        https://docs.google.com/presentation/d/1xUNDHMP_qTHH1wA3m0yCmWVf_sHp41Qd7Opq3FhgINs/edit?
        usp=sharing.
        I believe this is of critical importance at this juncture. If I did
        not think so, I would not bother trying. I have detailed all the
        rationale here:
        https://docs.google.com/document/d/1U2qEqF9K969t5b3YuX4cwex5LJPvF3bt1w27cdKNpDM/edit?
        usp=sharing.
        For those that recall, something very similar was done for Jakarta EE
        11, so this isn't exactly without precedent.

        I would like to see if this can be done in the following couple of
        weeks, when the Program Plan is due.

        Thanks,

        Reza


Reza Rahman

Principal Program Manager

Java on Azure at Microsoft

reza.rahman@xxxxxxxxxxxxx

+1 717 329 8149


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