Add jlink-compatible Java9/Jigsaw module-info (not automatic modules)

[xzel23]

Latest version has automatic modules and can be used in Java 9 projects (#114). However, this is not compatible with the jlink tool.

Steps to reproduce the problem (provide example input):

• create a Java 9 based project that uses modules
• Use jlink

Expected behavior:

jlink links the prokect

Actual behavior:

jlink reports an error:

> Task :link FAILED
Error: automatic module cannot be used with jlink: org.commonmark.ext.gfm.strikethrough from file:///Users/axel/.gradle/caches/modules-2/files-2.1/com.atlassian.commonmark/commonmark-ext-gfm-strikethrough/0.11.0/2b3f085711511202c380f2540760d64302c6bb7e/commonmark-ext-gfm-strikethrough-0.11.0.jar

[xzel23]

I think module-info should be added in a Java 8 compatible way. I have done it for some libraries that use the gradle build tool, so it should be possible in Maven too. If noone is working on this, I will try to do this myself, but. since I have no experience in Maven, it might take some time.

[robinst]

Apparently adding a module-info breaks Android usage, quoted from Stephen's blog post:

And just for kicks, your project can no longer be used by Android (as the team there seems to be very slow in adding a simple "ignore module-info" rule).

[xzel23]

Well, then I'd keep it in a separate branch until Android and other tools catch up. But Reducing download size by more than 100 MB when packaging your app is a big "positive benefit" of Java JPMS.

Would have been nice if Stephen had added the different bug reports for the issues he mentions so that we could begin hacking away those issues instead of just complaining that support is still not there.

[robinst]

I'm not a fan of having a separate branch that needs to be kept up to date. Releasing a duplicate set of artifacts would be possible for Java 9+ (with a different group ID or artifact IDs), but that is also a lot of effort and would add confusion.

How would you feel about having a script that can process a set of jars to add the module-info? Would that work for you use case?

[xzel23]

I think that would not really help the situation. IMHO JPMS has huge benefits once it's there, but we will never get there unless libraries are updated to include module-info. And that can already be done in a Java 8 compatible way. Thats's what should be done and will be of benefit for us all.

I can however see your point about Android and tools not being ready. IMHO those tools should be fixed as soon as possible. I have already started adding module.info in my own fork of commonmark and maybe will even publish jars (with version "xxx-JPMS" on bintray) that are still compatible with Java 8, but not android and the tools you mentioned.

Once Java 11 (the next LTS) is out, we should look at this again and the issues with android and tools are solved, can merge my changes into master.

BTW, if anyone has links to the bug reports concerning the issues described in Stephen's blog, maybe they could be added here so that we can track progress and/or even help fixing.

[robinst]

I feel you. At the same time I'm also being asked to support Android, e.g. see #124.

Once Java 11 (the next LTS) is out, we should look at this again and the issues with android and tools are solved, can merge my changes into master.

Yeah, sounds good.

This issue might be good to watch too: https://github.com/google/guava/issues/2970

[xzel23]

Ok, I have a works-for-me solution now. I added module-info.java, but compile all other files with targetCompatibility Java 8. module-info.java is compiled in Java 9 mode and a multi-release jar is created. This should hopefully be a solution that works for Java 8 as well as Android. The problem is my knowledge with Maven is quite limited, and so I did it in gradle (using a plugin I created to help with modularising libraries).

I can use the library in my jlinked standalone application, but I don't use all plugins (just gfm-tables and fm-strikethrough), so there might still be issues with the other plugins. If anyone wants to try, just write to me. If there's interest and I find the time to set it up, I could provide binaries of my jpms-version via bintray.

I think the module-info files could be easily merged back, but someone clever would have to help with the Maven part:

• remove all module-info.java files from the "normal" sorceset
• compile all module-info.java with targetCompatibility Java 9 and move the resulting class files to META-INF/versions/9
• set the Multi-Release to true in the POM

[xzel23]

If anyone else is interesteed: A modularized version with all 6 plugins usable with jlink is available here (binaries on bintray): https://github.com/xzel23/commonmark-java.

I will try to keep track of new releases of commonmark-java and update my fork and provide binaries for new releases.

[ice1000]

If anyone else is interesteed: A modularized version with all 6 plugins usable with jlink is available here (binaries on bintray): https://github.com/xzel23/commonmark-java.

I will try to keep track of new releases of commonmark-java and update my fork and provide binaries for new releases.

Bintray is closed, do you have plan to publish to maven central?

[cichte]

Hi, love the lib, but also get the error: automatic module cannot be used with jlink: org.commonmark. I am developing on JDK 16.0.2 and have to build the app with maven and jlink. The modularized version from @xzel23 doesnt do the job... Is there any chance to get the lib jlink compatibel in 2021? :-) Any help is appreciated...

[ice1000]

Hi, love the lib, but also get the error: automatic module cannot be used with jlink: org.commonmark. I am developing on JDK 16.0.2 and have to build the app with maven and jlink. The modularized version from @xzel23 doesnt do the job... Is there any chance to get the lib jlink compatibel in 2021? :-) Any help is appreciated...

How doesn't the modularized version do the job? What did you try and what did you get v

[cichte]

The artifact com.atlassian.commonmark from here ->https://github.com/xzel23/commonmark-java caused an error because was moved as describe here

https://mvnrepository.com/artifact/com.atlassian.commonmark/commonmark

to here

https://mvnrepository.com/artifact/org.commonmark/commonmark/0.18.1

This was the artifact i used:

        <dependency>
            <groupId>org.commonmark</groupId>
            <artifactId>commonmark</artifactId>
            <version>0.18.1</version>
        </dependency>`

And i get this Message:

Error: automatic module cannot be used with jlink: org.commonmark from file:///C:/Users/developer/.m2/repository/org/commonmark/commonmark/0.18.1/commonmark-0.18.1.jar [ERROR] Command execution failed.

This was the point i get lost :-)

[ice1000]

I think you should checkout this branch: https://github.com/xzel23/commonmark-java/tree/0.14.0-jigsaw

I think the xzel23 didn't update the README to his artifacts, so you're actually using the artifact of this repo.

[cichte]

Thank you for the hint. I tried now all Versions from 0.13.1 up to 0.16.1 ... all with the same result:

Error: automatic module cannot be used with jlink: org.commonmark from file:///C:/Users/developer/.m2/repository/com/atlassian/commonmark/commonmark/0.13.1/commonmark-0.13.1.jar
[ERROR] Command execution failed.

There is an automatic-module-name declaration in the jars manifest:

Automatic-Module-Name: org.commonmark

There ist also no module-info.java in the jar, so i think jlink isnt wrong with its suggestion.

[ice1000]

Yes there aren't. Why are you using the ones without them? Just use the ones with them.

[cichte]

Yes there aren't. Why are you using the ones without them? Just use the ones with them.

Seems the maven-repos are outdated, or wrong?

I cloned the git-repo now and try my own build. Thanks :-)

[ice1000]

Seems the maven-repos are outdated, or wrong?

Wrong.

I cloned the git-repo now and try my own build. Thanks :-)

Yes, that's (supposed to be) the correct way to do it :-)

Maybe I'll try to maintain a fork with Jigsaw things and publish it to another maven repository, with the appropriate licenses.

[ice1000]

As long as I am still using commonmark

[ice1000]

Folks I've created a fork https://github.com/aya-prover/commonmark-java based on @xzel23's work. I've released it on maven central, but it may take a few days to be usable (there's a staging process). Lmk if there is any problem (some subprojects are not published because I don't need them. If you need me to publish them please lmk too)

[miasma]

Folks I've created a fork https://github.com/aya-prover/commonmark-java based on @xzel23's work. I've released it on maven central, but it may take a few days to be usable (there's a staging process). Lmk if there is any problem (some subprojects are not published because I don't need them. If you need me to publish them please lmk too)

Hi - I tried using your fork, but unfortunately run into issues. I noticed the 0.19.0 version of the org.aya-prover:commonmark seems to be missing. Can't find it via the published Maven repo. The bytecode of the older 0.18.1 version also triggers this issue when compiling a simple project

$ mvn clean compile jlink:jlink
...
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.10.1:compile (default-compile) on project test-project: Compilation failure
[ERROR] /home/foo/test-project/src/main/java/module-info.java: class file for /home/foo/.m2/repository/org/aya-prover/commonmark/0.18.1/commonmark-0.18.1.jar(/module-info.class) uses preview features of Java SE 11.
[ERROR]   (use --enable-preview to allow loading of class files which contain preview features)

The bytecode decoder in IDEA mentions that your library is using bytecode version 55.65,535 (Java 11-preview). The normal Java 11 bytecode version is 55.0.

Are there still major issues with multi-release jars? Can't the official project support JPMS already? Maven's official documentation shows examples of building MR jars for JPMS projects that are backwards compatible.

[ice1000]

Hi - I tried using your fork, but unfortunately run into issues. I noticed the 0.19.0 version of the org.aya-prover:commonmark seems to be missing. Can't find it via the published Maven repo.

Nice catch, I've fixed that.

The bytecode of the older 0.18.1 version also triggers this issue when compiling a simple project The bytecode decoder in IDEA mentions that your library is using bytecode version 55.65,535 (Java 11-preview). The normal Java 11 bytecode version is 55.0.

I've fixed it too.

See 0.19.1 version, it may take some time to upload

[redcatbear]

I ran into problems with the missing module-info too and created #275 until I realized that this is basically a duplicate of this ticket here, so I closed #275 again. In my case Maven's surefire tests did not run because of missing exports. Still hoping that this ticket gets solved.

[ice1000]

@redcatbear What do you think about https://github.com/aya-prover/commonmark-java?

[redcatbear]

@ice1000 , I will give that a try. Thanks.

[robinst]

Hey everyone. I think it's time we modularized commonmark-java itself. I don't think Android tooling has a problem with module-info files anymore (that was the original blocker).

I'm gonna look at @ice1000's work as a starting point. One tricky part is going to be that until now, the classes in the internal package were accessible and I know some people have used them to extend inline parsing. If we no longer export those it's going to be harder. But maybe this is a good point in time to actually make those things public. There's some work that happened as part of https://github.com/commonmark/commonmark-java/issues/113 already.

I can't commit to a time frame at this point though.

[miasma]

This project also depends on https://github.com/robinst/autolink-java, which doesn't provide any module-info file yet.

[aalmiray]

I'd suggest looking at ModiTect. It can generate/append module-info to a JAR while keeping the codebase compatible with Java 8. The generated module-info.class will be placed inside /META-INF/versions/x (turning the JAR into a Multi Resource JAR) which should avoid any further problems with Android.

If interested I can send a PR to get the ball rolling. I've done it successfully with other projects that also require Java 8 compatibility.

Here's how the current setup with automatic module name looks like:

aalmiray2:lib aalmiray$ jarviz module name --file commonmark-0.21.0.jar 
subject: commonmark-0.21.0.jar
name: org.commonmark
source: manifest
automatic: true
valid: true

$ jarviz module descriptor --file commonmark-0.21.0.jar 
subject: commonmark-0.21.0.jar
name: org.commonmark
version: 0.21.0
open: false
automatic: true
requires:
  java.base mandated
contains:
  org.commonmark
  org.commonmark.internal
  org.commonmark.internal.inline
  org.commonmark.internal.renderer
  org.commonmark.internal.renderer.text
  org.commonmark.internal.util
  org.commonmark.node
  org.commonmark.parser
  org.commonmark.parser.block
  org.commonmark.parser.delimiter
  org.commonmark.renderer
  org.commonmark.renderer.html
  org.commonmark.renderer.text

[robinst]

@aalmiray Thanks for the offer, but I've already been working on the change to just make it modular. It's in a PR now: https://github.com/commonmark/commonmark-java/pull/286

[aalmiray]

I see. Unfortunately the changes in that PR bump the whole codebase to Java9. I was hoping that commonmark remained Java8 compatible for a bit longer. That’s what the ModiTect plugin enables. The module-info class may be auto generated or taken from an existing source file. It’ll be compiled using ASM and placed under META-INF/versions, turning JARs into multi resource JARs. This satisfies consumers on Java 8 and greater.

[robinst]

I was hoping that commonmark remained Java8 compatible for a bit longer.

@aalmiray Why? Still have projects stuck on Java 8? I could consider maintaining 0.21.x versions with bug fixes for Java 8 (probably not many necessary), but I really want to move on from an almost 10 year old Java version and not have to make the build more complicated.