Hello Yeray,

   Comments below:

On Wed, Mar 29, 2023 at 3:59 PM Yeray Borges Santana <yborgess@redhat.com> wrote:

Hello Richard,

Accordingly with your description, instead of only removing the usage, it looks like ibm.jdk module can be (and should be) completely removed from WildFly Core since it is meant for JDK 8. If so, it means [7] and the WildFly counterpart PR needs some changes.

I plan to do these deprecated modules cleanup in two phases:

 * First remove their usages

 * Second somewhere in near future remove them from WildFly completely

To answer your question: Yes ibm.jdk module can be removed from WildFly completely as it will not cause any harm. It is exposing just IBM JDK8 internals.

Notice we have already merged [6] and [9] without a proper discussion first, but due to the silence on this topic it seems we could be fine.

I apologize for my silence on this topic. I was asked by Brian (and he was right) to open discussion about these upcoming changes.

With the current status, if there is an application incompatibility because those modules are no longer made available to the deployments, the simple solution is to add them back via deployment structure since the modules are still available, although deprecated. In any other case, let us know so we can act in consequence before releasing WF28.

Correct. But a better solution is to declare dependency only on JDK internal modules that are really needed and not use our deprecated modules.

 

To be clear it is not documented anywhere which modules are automatically available to deployments by default.

In the past when something was not working for us or our users we tended to unlock these JDK internals

via sun.jdk or ibm.jdk modules so they started to work auto-magically. After many years sun.jdk and ibm.jdk modules became garbage modules.

In the meantime Java was modularized and its modules standardized. Now we and our

users know which JDK internal modules they need to depend on when they want to use them.

That could be the less aggressive approach; remove them from the deployments in WF28 and completely remove them in WF29 for example.

Yes. That sounds like a good plan.

If you get your application affected due to the removal from the deployments, you can easily workaround by adding them again via jboss-deployemnt-structure, but you have to know that they will be completely removed in the following release so you need to adapt your applications for such removal or raise any issues if WildFly doesn't provide a valid alternative for your use case.

That shouldn't happen. Every JDK internal API that was exposed via sun.jdk module is available in some JPMS module.

Java users know which JPMS module they want to use in their application.

On Mon, Mar 20, 2023 at 3:56 PM Richard Opalka <ropalka@redhat.com> wrote:

   At the time when first modular Java was released in September 2017 [0]
JBoss Modules team have already been working on proper integration with it [2].
That effort was finished 7 months later after Java 9 initial release and
JBoss Modules version supporting Java's JPMS modules was integrated into
WildFly in April 2018.

During the JBoss Modules 1.8.0.Final merge into WildFly some legacy and
WildFly specific modules have been deprecated, see [2] and [3]. These are:

 * ibm.jdk (aggregation module for IBM JDK8 internals)
 * javax.api (aggregation module for some Java's official APIs)
 * javax.xml.stream.api (streaming api)
 * javax.sql.api (sql api)
 * sun.jdk (aggregation module for SUN JDK internals)

   We created and defined these modules over time as WildFly was developed and before
Java got modularized via [5]. But with introduction of modular Java everything changed
and there is no more reason to use these legacy modules that we came up in the past.
It is preferred and recomended to use official Java JPMS modules instead.

   All five obsolete modules were deprecated in the past but second important step
of removing references on them wasn't completed yet and so they are still being used
in both WildFly and WildFly Core. Now before EAP8 goes final is the right time
to clean it up and complete the migration to standard Java's JPMS modules and ideally
get rid of these five deprecated modules. Another option is to keep them (although
unreferenced) in WildFly & EAP8 for backwards compability.

   There were identified two areas of above deprecated modules usages:
 a) module.xml files in WildFly Core and WildFly
 b) server runtime code

   To migrate to Java JPMS modules it is important to know which JPMS module(s) should be
used/referenced instead. Following is the mapping of legacy WildFly modules to Java JPMS modules:

 1) ibm.jdk deprecated module cannot be migrated to standard Java JPMS module. This module was introduced
    because we needed some of IBM JDK8 internals to be available in WildFly in the past.
    When WildFly Core and WildFly code base moved to modular JDKs (JDK11  and above) this legacy module
    is not needed anymore. It is because recent IBM JDK 11 and above are based on OpenJDK and its JPMS modules architecture.
    References to that module can be eliminated completely without any further migration.

 2) javax.api deprecated module will be replaced with one or some of the following JPMS modules it aggregates:
    - java.se
    - jdk.xml.dom
    where java.se is also Java's JPMS aggregation module and it can be further dereferenced to smaller JPMS modules that are only needed

 3) javax.xml.stream.api will be replaced with java.xml JPMS module

 4) javax.sql.api deprecated module will be replaced with one or some of the following JPMS modules it aggregates:
    - java.sql
    - java.sql.rowset
    - java.transaction.xa

 5) sun.jdk deprecated module will be replaced with one or some of the following JPMS modules it emulates:
    - modules whose name starts with jdk. prefix (note these are specific to the JDK and will not necessarily be available in all Java implementations)

   The last remaining bit we would like to clarify and standardize with this cleanup effort
is server runtime code referencing these legacy WildFly modules. It was identified that WildFly server propagates:
 * javax.api
 * ibm.jdk
 * sun.jdk
 * org.jboss.vfs
modules to all deployments by default.

   In order to standardize WildFly and EAP8 deployments we propose the following changes:
 * only java.se JPMS module will be propagated to all deployments by default - was addressed with [6]
 * deprecated ibm.jdk will not be propagated anymore to all deployments by default - will be addressed with [7]
 * deprecated sun.jdk will not be propagated anymore to all deployments by default - will be addressed with [8]
 * org.jboss.vfs will not be propagated to all deployments - was addressed with [9]
This proposal of course introduces a potential (but fixable) backward incompatibility issue between EAP7 and EAP8 deployments.
Deployments that were relying on sun.jdk module or org.jboss.vfs module to be available in their deployments by default will need to be fixed
to reference org.jboss.vfs module or jdk. prefixed JPMS modules explicitly - for example see [10].

Best regards,
JBoss Modules Team

[0] https://en.wikipedia.org/wiki/Java_version_history - Java release dates
[1] https://issues.redhat.com/browse/MODULES-254 - Support for dependency on Jigsaw modules from static modules
[2] https://issues.redhat.com/browse/WFCORE-3705 - Allow dependencies on JDK modules
[3] https://issues.redhat.com/browse/WFCORE-3684 - Upgrade JBoss Modules to 1.8.0.Final
[4] https://issues.redhat.com/browse/WFCORE-6248 - Only Java SE aggregation module should be visible to all deployments by default
[5] https://openjdk.org/jeps/200 - JEP 200: The Modular JDK
[6] https://issues.redhat.com/browse/WFCORE-6237 - Eliminate usage of deprecated javax.api module
[7] https://issues.redhat.com/browse/WFCORE-6245 - Eliminate usage of deprecated ibm.jdk module
[8] https://issues.redhat.com/browse/WFCORE-6249 - Eliminate usage of deprecated sun.jdk module
[9] https://issues.redhat.com/browse/WFCORE-6250 - Don't include org.jboss.vfs module to all deployments by default
[10] https://issues.redhat.com/browse/WFLY-17666 - Deployments using RMI Java Naming provider must define explicit dependency on jdk.naming.rmi JPMS module

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