users@javaee-spec.java.net

[javaee-spec users] Re: [jsr374-experts] Re: JPA_SPEC-145, JPA_SPEC-146: Provide supportforJDK9 module system

From: Werner Keil <werner.keil_at_gmail.com>
Date: Thu, 4 May 2017 22:25:06 +0200

Dmitry,

Nobody proposes to refer to modules in the spec (the written document where
a JSR comes with it)
A module definition like
https://github.com/javaee/jsonb-spec/blob/master/api/src/main/java/module-info.java
exposes the API, not RI, or are you saying you'd rather remove that on the
API level for now?

This file even shows the inter-dependency between JSON-B and JSON-P, there
are certainly other cases like JSP or JSF using Servlet, etc. If an
application also uses either of these modules and the module changes with
EE 9 or a MR to the EE 8 content, it forces a change to that application.

On the other hand, what we see around Java 9 including a hard time to even
approve Jigsaw without some improvement and fixes, it still is going to be
a great challenge to existing applications running Java 6, 7 or 8, so a
changed module name is probably not the biggest barrier to use Java SE or
EE 9 here ;-)

Regards,
Werner


On Thu, May 4, 2017 at 9:57 PM, Dmitry Kornilov <dmitry.kornilov_at_oracle.com>
wrote:

> Werner, I don’t understand what are you proposing. Bill made a clear
> statement that modules must not be a part of specs. I agree with it. If
> module is defined in an RI it doesn’t affect Java EE 8 at all because it’s
> Java 8 based. On the other hand, some implementation, like JSON-P or Yasson
> are designed to work in Java SE environment as well. It makes sense making
> them JDK9 compatible. We follow naming convention proposed by Java team
> (see email from Lukas below). If future versions of Java EE define
> different module name convention, we will rename the modules.
>
>
>
> Thanks,
>
> Dmitry
>
>
>
> *From: *<werner.keil_at_gmail.com>
> *Reply-To: *<jsr374-experts_at_json-processing-spec.java.net>
> *Date: *Thursday, 4 May 2017 at 20:34
> *To: *Bill Shannon <bill.shannon_at_oracle.com>, "users_at_javaee-spec.java.net"
> <users_at_javaee-spec.java.net>, "users_at_jpa-spec.java.net" <
> users_at_jpa-spec.java.net>
> *Cc: *"jsr374-experts_at_json-processing-spec.java.net" <jsr374-experts_at_json-
> processing-spec.java.net>, "pmo_at_jcp.org" <pmo_at_jcp.org>, Linda DeMichiel <
> linda.demichiel_at_oracle.com>
>
> *Subject: *[jsr374-experts] Re: JPA_SPEC-145, JPA_SPEC-146: Provide
> supportforJDK9 module system
>
>
>
> Just an example, so far all JSRs are supposed to use „java“, while some
> internal parts of the JDK have a „jdk“ module prefix, so just something it
> might change to. It does not matter what it changes to, the Change as such
> will certainly make it harder to upgrade from Java EE 8 to 9 ;-/
>
>
>
> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for
> Windows 10
>
>
>
> *From: *Bill Shannon <bill.shannon_at_oracle.com>
> *Sent: *Thursday, May 4, 2017 20:30
> *To: *werner.keil_at_gmail.com; users_at_javaee-spec.java.net;
> users_at_jpa-spec.java.net
> *Cc: *jsr374-experts_at_json-processing-spec.java.net; pmo_at_jcp.org; Linda
> DeMichiel <linda.demichiel_at_oracle.com>
> *Subject: *Re: [jsr374-experts] Re: JPA_SPEC-145, JPA_SPEC-146: Provide
> supportforJDK9 module system
>
>
>
> What's this JEE you're talking about?
> <https://javaee.github.io/javaee-spec/JEE>
>
> Yes, all module names.
>
> werner.keil_at_gmail.com wrote on 05/04/2017 11:15 AM:
>
> All module names even those by individual modules like the ones Dmitry or
> Lukas defined for JSR 374?!!
>
>
>
> That would be rather inconsistent and annoying. Some artifactIds of JSRs
> like Servlet etc. also changed to contain the „javax.servlet“ string or
> similar, but if 374 or any other Java EE JSR called their module
> „java.json“ right now, and was forced to rename it to say „jee.json“ later,
> it would make it difficult for modules consuming it.
>
>
>
> If only the Umbrella JEE module had any given Name and respected
> individual modules following the current JCP Guideline, that’s something
> else, I would not see much of a Problem with that.
>
>
>
> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for
> Windows 10
>
>
>
> *From: *Bill Shannon <bill.shannon_at_oracle.com>
> *Sent: *Thursday, May 4, 2017 20:04
> *To: *users_at_javaee-spec.java.net; users_at_jpa-spec.java.net
> *Cc: *jsr374-experts_at_json-processing-spec.java.net; pmo_at_jcp.org; Linda
> DeMichiel <linda.demichiel_at_oracle.com>
> *Subject: *[jsr374-experts] Re: JPA_SPEC-145, JPA_SPEC-146: Provide
> support forJDK9 module system
>
>
>
> I agree, and that's what I've told our team.
>
> None of our Java EE 8 specs should reference SE 9 modules.
>
> On the other hand, if the reference implementations accommodate SE 9
> modules, I'm fine with that. But the module names won't be a JCP standard
> and thus would be subject to change when defined by a future standard.
>
> Kevin Sutter wrote on 05/03/2017 02:24 PM:
>
> We should not be incorporating Java SE 9 module definitions into
> individual Java EE specifications without the proper guidance from the Java
> EE Platform. We have to be consistent with this effort. I know some of
> the older Java EE specs that have been incorporated into Java SE have been
> defining MRs with the required Java SE 9 updates. But, since Java EE 8
> only requires Java SE 8, we should not be defining Java SE 9 module info in
> these "child" specifications. This should be a platform requirement that
> filters down to the child specs.
>
> ---------------------------------------------------
> Kevin Sutter
> STSM, Java EE and Java Persistence API (JPA) architect
> e-mail: sutter_at_us.ibm.com Twitter: @kwsutter
> phone: tl-553-3620 (office), 507-253-3620 (office)
> LinkedIn: https://www.linkedin.com/in/kevinwsutter
>
>
>
> From: Lukas Jungmann <lukas.jungmann_at_oracle.com>
> <lukas.jungmann_at_oracle.com>
> To: users_at_jpa-spec.java.net
> Cc: jsr374-experts_at_json-processing-spec.java.net, pmo_at_jcp.org,
> users_at_javaee-spec.java.net
> Date: 05/03/2017 03:28 PM
> Subject: [jpa-spec users] Re: [jsr374-experts] Re: JPA_SPEC-145,
> JPA_SPEC-146: Provide support for JDK9 module system
>
> [image: id:image001.png_at_01D2C513.38F97A10]
>
>
>
>
> [forgot to cc others in my original reply]
>
> --lukas
>
>
> On 5/3/17 9:24 PM, Werner Keil wrote:
> Lukas,
>
> Thanks a lot for the pointer especially the JEP and its mention of a
> standard namespace for all JCP defined artifacts. That'll help.
>
> Regards,
> Werner
>
>
> On Wed, May 3, 2017 at 7:09 PM, Lukas Jungmann <lukas.jungmann_at_oracle.com>
> wrote:
> Hi Werner,
>
>
> On 5/3/17 6:24 PM, Werner Keil wrote:
> Lukas,
>
> Thanks for bringing that up.
>
> I was wondering, if there is a common pattern all (Java EE) JSRs are
> supposed to follow for making the JSRs Java 9/Jigsaw compatible?
>
> JSON-B https://github.com/javaee/jsonb-spec/blob/master/
> api/src/main/java/module-info.java
> and JSON-P https://github.com/javaee/jsonp/blob/master/api/
> src/main/jdk9/module-info.java
> already got a module-info (at least for JSR 374 it was also you who
> created or last changed it;-)
>
> right, I was the one who created it for JSON-P and suggested JSON-B to use
> it as well. The idea behind it was that JSON-B is fresh new, simple API
> targeted to Java SE 8+ and with JDK 9 release coming it made sense to me to
> try to align JSON-B with it (...so MR won't be needed later just because of
> JDK9). JSON-P was kind of consequence of this since JSON-B depends on
> JSON-P...
>
> Unfortunately I don't think there's common pattern to make JSRs Java 9
> compatible except of those being part of JDK 9 (eg. JSR-67 (SAAJ), JSR-222
> (JAXB) and JSR-224 (JAX-WS) on which I've been working on as well)
>
>
> As for this spec/JPA 2.2 MR - I'm not strictly against not defining module
> name (and I'd actually prefer to define it as soon as provider-agnostic JPA
> API artifact becomes available) but since there is currently no
> provider-agnostic JPA API artifact, it does not make much sense to me at
> this point.
>
>
> Based on module naming by the JDK itself, should we take
> "java.<something>" as a module name to be the preferred name for both the
> JDK and all JSRs under jcp.org?
>
> Or are there other preferences e.g. "javax.<something>" to match the Maven
> GroupId of most Java EE JSRs especially those by Oracle?
> see https://github.com/javaee/jsonp/blob/master/api/pom.xmlfor JSR 374.
>
> A former EG Member of JSR 363 also asked this in our list and we discussed
> what would be a good module name there, but wanted to wait for official JCP
> guidance if possible.
>
> the only official naming convention I'm aware of is defined by
> http://openjdk.java.net/jeps/200which states that:
>
> 1. Standard modules, whose specifications are governed by the JCP, must
> have names starting with the string "java.".
>
> ...that should answer your question ;-)
>
> Thanks,
> --lukas
>
>
>
> Thanks and Regards,
> Werner
>
>
> On Wed, May 3, 2017 at 6:13 PM, Lukas Jungmann <lukas.jungmann_at_oracle.com>
> wrote:
> Hi,
>
> Since the release of JDK 9 is behind the corner, it would be good to
> update the spec to be ready for it.
> I can see 2 things which can be done:
>
> 1) JPA_SPEC-145: define module name
>
> I'm not 100% sure this needs to be done but for the sake of completeness -
> it is clear that the module name should be 'java.persistence'. While it
> would be nice to have the name defined and available, do we really need
> this or should we stick with API being resolved on JDK9 as an automatic
> module?
>
> I'm proposing to NOT touch this area in the spec now and keep this up to
> the provider. Any opinions?
>
> 2) JPA_SPEC-146: Use ServiceLoader facility
>
> with the introduction of the module system there are currently 2 ways, how
> persistence provider implementation can be defined - META-INF/services and
> module-info with 'provides ... with...'. Former way is already covered but
> the latter is not, so I'd like to propose following change to Section 9.2
> of the spec (additions are in italics, removals are striked-through italics)
>
> *Section 9.2 Bootstrapping in Java SE Environments*
>
> In Java SE environments, the Persistence.createEntityManagerFactory
> method is used
> by the application to create an entity manager factory.
>
> A persistence provider implementation running in a Java SE environment
> should also act as a service
> provider by supplying a service provider configuration *file as described
> in the JAR File Specification*.
> *The Persistencebootstrap class should use ServiceLoader facility to
> locate all available provider implementations.*
>
> The provider configuration *file* serves to export the provider
> implementation class to the Persistence
> bootstrap class, positioning the provider as a candidate for backing named
> persistence units.
> The provider may supply the provider configuration file by creating a text
> file named javax.persistence.spi.PersistenceProvider
> and placing it in the META-INF/services directory of
> one of its JAR files. The contents of the file should be the name of the
> provider implementation class of
> the javax.persistence.spi.PersistenceProvider interface.
>
> Example* 1*:
> A persistence vendor called ACME persistence products ships a JAR called
> acme.jar that contains
> its persistence provider implementation. The JAR includes the provider
> configuration file.
>
> acme.jar
> META-INF/services/javax.persistence.spi.PersistenceProvider
> com.acme.PersistenceProvider
> …
>
> The contents of the META-INF/services/javax.persistence.spi.
> PersistenceProvider
> file is nothing more than the name of the implementation class:
> com.acme.PersistenceProvider.
>
>
>
>
>
>
>
>
>
>
>
>
>
> *Example 2:A persistence vendor called ACME persistence products ships a
> module called acme.jar that provides persistence provider implementation.
> The JAR contains module definition which contains the name of the
> implementation class.acme.jar module-info.class …module acme { provides
> javax.persistence.spi.PersistenceProvider with
> com.acme.PersistenceProvider; …}The source code of the provider's module
> definition must contain the name of the provider’s implementation class.*
>
>
> Persistence provider jars may be installed or made available in the same
> ways as other service providers,
> e.g. as extensions*,* or added to the application classpath according to
> the guidelines in the JAR File
> Specification *or added to the application module path according to the
> guidelines in the Java Platform Module System specification*.
>
> Do you think this is fine, something should be corrected or is there a
> reason why this second part should not be added to JPA 2.2 MR?
>
> Thank you,
> --lukas
>
> [1]: https://java.net/jira/browse/JPA_SPEC-145
> [2]: https://java.net/jira/browse/JPA_SPEC-146
>
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