Re: [jakarta.ee-spec.committee] Incremental vs Big Bang boms

["Kazumura, Kenji" <kzr@xxxxxxxxxxxxxx>]

Assume that you have an existing Jakarta EE 8 app, 
and you want to change just your own business logic,
but you don't want to use any new features in Jakarta EE 9.
You don't need to change the package names in your source code when using incremental bom,
while you need to change all the package names in your source when using big bang bom.

If we choose the big bang approach, this type of customers do not have motivation to use Jakarta EE 9.
My concern is, if a vendor has a lot of this type of existing customers,
this vendor also does not have motivation to provide Jakarta EE 9 products.

-Kenji Kazumura


> -----Original Message-----
> From: jakarta.ee-spec.committee-bounces@xxxxxxxxxxx
> [mailto:jakarta.ee-spec.committee-bounces@xxxxxxxxxxx] On Behalf Of Bill Shannon
> Sent: Thursday, May 30, 2019 6:10 AM
> To: Scott Stark <sstark@xxxxxxxxxx>
> Cc: Jakarta specification committee <jakarta.ee-spec.committee@xxxxxxxxxxx>
> Subject: Re: [jakarta.ee-spec.committee] Incremental vs Big Bang boms
> 
> If you have an existing app that's using the Jakarta EE 8 bom and you
> update part of that app to use the new features in Jakarta EE 9, e.g.,
> the jakarta.ws.rs.Path class, you'll need to add something to your app
> configuration to get access to the new API, either by adding the entire
> Jakarta EE 9 bom or by adding the adding the new Jakarta RESTful Web
> Services API pom.
> 
> That's the same with Incremental or Big Bang.
> 
> 
> Scott Stark wrote on 5/29/19 1:43 PM:
> > Let's focus on javax.ws.rs.Path moving to jakarta.ws.rs.Path, and I have updated updated a Jakarta EE 8 app to
> Jakarta EE 9 where the only change was in the REST spec. I expect that the Jakarta EE 9 bom will have:
> > - under incremental, the jakarta.ws.rs.* + all unmodified javax.* spect artifacts.
> > - under Big Bang, the  jakarta.ws.rs.* + all jakarta.* spec artifacts that simply had a package name change.
> >
> > If I am using the incremental bom, I will only be able to compile my updated Jakarta EE 8 app if I have replaced
> all of the javax.ws.rs.Path usage.
> > If I am using the Big Bang bom, and I have only incrementally updated my app to what has functionally changed,
> then I also need to include the Jakarta EE 8 bom. Any location where I forgot to update javax.ws.rs.Path usage will
> be treated as Jakarta EE 8 and the binary compatibility layer will kick in.
> >
> >> On May 29, 2019, at 12:56 PM, Bill Shannon <bill.shannon@xxxxxxxxxx> wrote:
> >>
> >>>
> >>> If I have a Jakarta EE 8 app that is updated to use the new REST apis, it
> >>> would need to include both Jakarta EE 8 and Jakarta EE 9 boms to compile the
> >>> app. Do we envision having a compatibly bom such that there is a single bom a
> >>> user could use to still build from source against? The concern here is that
> >>> they intended to update all REST api usage to the Jakarta EE 9 apis, but
> >>> missed some locations. If they have to include both Jakarta EE 8 and Jakarta
> >>> EE 9 boms, this would be masked. If there was a Jakarta EE 9 compatibility
> >>> bom, compiling against it would fail on the locations that did not update
> >>> from JAX-RS to the Jakarta EE 9 REST apis.
> >>
> >> That would only be an issue with the incremental approach where the bom
> >> would have the jakarta.rest.* APIs but not the javax.ws.rs.* APIs, right?
> >>
> >> If compatibility works by effectively "aliasing" the javax names to the
> >> jakarta names, an app, or even a class, could mix and match javax names
> >> and jakarta names and still work.  (Whether fine grained mixing is a good
> >> idea is a separate issue.  :-))  And yes, it would need to depend on the
> >> appropriate bom(s) or pom(s) to get access to the APIs it needs.
> >>
> >>
> >> Whether there's a "compatibility bom" and what it's called would seem to
> >> depend on whether compatibility is a Jakarta EE spec of some sort or whether
> >> it's left completely to products to provide.  In any event, there would
> >> continue to be the Jakarta EE 8 bom.
> >
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