[jax-rs-spec users] [jsr339-experts] Re: MVC

From: Sergey Beryozkin <>
Date: Mon, 30 Jun 2014 10:36:55 +0100

Hi Markus
On 29/06/14 17:39, Markus KARG wrote:
> I gave the topic another thought from the aspect of Java EE as a platform
> (ignoring REST), and like to add that I see the technical merits of
> combining the two technologies JAX-RS and JSF into one. In coarse,
> redefining JSF to become an implementation of the JAX-RS 'Feature' interface
> providing Filters, Entity Providers and Exceptions Mappers, and dropping all
> its internal plumbing in favour of JAX-RS, is actually appealing. This won't
> change anything w.r.t. existing JAX-RS, but it would spare JSF
> implementations some duplicate code, obviously, as the JAX-RS-Servlet and
> the JSF-Servlet mostly do the similar things internally (path matching,
> parsing, rendering, exception handling, CDI, ...). The "simple" difference
> between JAX-RS and JSF is that the first is for machine users, the latter
> for human users.

This is simply not correct. JAX-RS is primarily about streamlining the
development of server-side REST or simple HTTP applications. People do
write Web UI applications today, including those depending on MVC. The
goal of the MVC effort has to be about providing a light-weight
standardized link between JAX-RS Responses and existing view processors.

The addition of client API to JAX-RS 2.0 just fills the gap to do with
the need of developers be able to write a standardized code for
consuming external HTTP applications but it does not turn JAX-RS as a
tool for machine users as such.

> So an existing JAX-RS application could become human-usable
> simply by adding JSF.jar (or enabling a "Use JSF" config property) and
> providing some nice facelets in theory.
> So my proposal would be, go with separated PDFs provided by a joint EG,
> keeping JAX-RS clean of MVC, but allow frameworks like JSF to use the
> technical core of JAX-RS if that is beneficial for them.
> As this topic mostly is driven by the frameworks needs, less by
> RESTafarians, I'd like to propose to invite at least Ed Burns to become a
> JAX-RS 2.1 Expert Group member so he can take care that we understood the
> JSF needs and he sees what he can drop once accepting JAX-RS as new
> foundation.

I don't have problems about JSF experts contributing to the effort for
JSF benefit from it, but I'd have major issues with it all becoming
about JSF.

Cheers, Sergey
> Regards
> Markus
> -----Original Message-----
> From: Markus KARG []
> Sent: Freitag, 30. Mai 2014 23:02
> To: ''
> Subject: RE: [jsr339-experts] Re: MVC
> Frankly spoken, I am not clear about the intention of adding MVC support
> particularly to JAX-RS. What do users expect to get in the end, keeping in
> mind that JAX-RS's very own target is to provide a framework for RESTful
> applications -- which by definition are stateless, while MVC is stateful,
> just like JSF is. Could it be the case that MVC, just as with SSE (see my
> other posting), is a candidate for a separate API built ONTOP of JAX-RS (an
> OPTIONAL extension to JAX-RS in a technical sense)? I think so, so if Bill
> Shannon likes to get that, and the JAX-RS EG group denies this to be
> RESTful, it might be an indicator that my proposal of splitting JAX-RS into
> "Java API for http" and "Things built ontop of that, like REST, SSE, and
> MVC" is valid and should be implemented. If JSF wants to get an MVC layer
> implemented by JAX-RS technology, the way to go then would be that "we"
> (JAX-RS) provide "Java API for http" (= the technology defined by JAX-RS
> currently), while the JSF guys *use* that to build their MVC stuff ontop.
> But frankly spoken, I do not see why "we" (JAX-RS) should provide MVC, is
> that is not REST.
> Regards
> -Markus
> -----Original Message-----
> From: Bill Burke []
> Sent: Freitag, 30. Mai 2014 21:12
> To:
> Subject: [jsr339-experts] Re: MVC
> On 5/23/2014 4:36 AM, Sergey Beryozkin wrote:
>> Hi
>> On 22/05/14 22:05, Santiago Pericas-Geertsen wrote:
>>> Dear Experts,
>>> As you may have seen in the Java EE 8 survey, there was significant
>>> interest in adding an MVC framework to the platform in EE 8. After
>>> some analysis, we are convinced that the best place for this work is
>>> in In fact, as many of you may recall, this was on our
>>> list for JAX-RS 2.0 but we've never got a chance to discuss it in any
>>> detail.
>>> I'm aware of some discussion in the JSF alias in relation to MVC in
>>> general, and its support as part of JAX-RS in particular. I plan to
>>> send an e-mail to the JSF alias as a way to establish a liaison
>>> between the two groups. I believe their expertise would be of great
>>> value for us and will help us design a framework that addresses the
>>> requirements of the EE community.
>> Look forward to JAX-RS supporting MVC and SSE. As far as the future
>> JAX-RS MVC is concerned, I hope it will not only target EE users
>> though :-). i.e, it would work even if no JSF is available, but of
>> course the input from JSF experts will be of great interest.
>> Using Jersey MVC as a template would be a nice start IMHO, we have a
>> less involved support for it, but I think it is close enough to the
>> way Jersey does it in some cases.
> I am 100% against MVC in JAX-RS. Are we really going to introduce a legacy
> and now defunct pattern to JAX-RS? The trend and future is Angular JS or
> GWT apps with simple RESTful back ends.
> This is wrong guys. You will regret adding and it will end up on the long
> list of Java EE features that nobody uses and bloat we'll have to support.
> SSE and now MVC, I'm really disappointed in the direction of JAX-RS.
> --
> Bill Burke
> JBoss, a division of Red Hat

Sergey Beryozkin
Talend Community Coders