Java Discontinuities in Practice

Nov 23, 2020, 4:04 PM

Tags: java

Earlier this year, I wrote a post about the lay of the Java land, and in it I mentioned the oddities of post-8 Java releases as well as the then-oncoming namespace conversion in Jakarta EE. Those changes are a bit more "real" now, so I think it's worth taking the opportunity to expand on them and how they relate to Java with Domino.

Jakarta EE 9

With Jakarta EE 9 officially out now, I think it's all the more important to keep an eye on what these changes are. For Jakarta's part, there's a convenient post up on Eclipse's site detailing the specifics of what's going on, and most of what I say here is really just going to rehash that.

The "namespace conversion" in question is the switch from javax.* to jakarta.* for EE-related packages like Servlet, due to Oracle not granting rights to the "javax" term. This has involved a lot of fiddly work internally for the Jakarta project as a whole, and all of the included specs have received a major-version bump to reflect the break. In general, these new versions are functionally equivalent to the previous release, but use the different package names - so Servlet 5 has the same capabilities as 4, JSF 3 as 2.3, and on down the line.

A bit of a quirk in this is that not all classes in the javax.* namespace will be moving to jakarta.*, because not everything in there was part of Java EE. For example, Swing is in javax.swing, but it's not going anywhere. It gets fiddlier, too, especially when it comes to XML. The JDK traditionally (more on that in a bit) contained a couple distinct technologies wrapped up under the javax.xml package space, but some of those are actually part of Java EE and make the transition to Jakarta. For example, the javax.xml.transform package (covering XSLT) is part of what was originally termed "Java API for XML Processing", or "JAX-P", and is still part of the Java SE core. The javax.xml.bind package (covering mapping between XML and Java objects) was part of the "Java Architecture for XML Binding" API, or "JAX-B", and is not part of Java SE anymore. It's now "Jakarta XML Binding" and is receiving a package change to jakarta.xml.bind. I think it's cases like these that will be hairy for a lot of people not doing full Jakarta EE 9 work.

For the most part, this won't have an effect on Java development on Domino for a good while. Domino has never tracked changes in the EE world - XPages was a partial fork of Java EE 5 and that's been about it. I think that the ways it will affect Domino development (other than if you just outright do Jakarta EE development, which you should) is that code examples and third-party libraries are going to gradually transition over to the new namespaces, making them incompatible with code in the Domino stack. This will certainly affect things like my XPages Jakarta EE Support project, where future versions of the implementation components won't be usable directly if they use the Servlet spec, even if they don't require Servlet 3+ functionally.

So I think it's worth being aware of what's going on, even if there's not (yet) anything you need to do about it. The same applies to the changes in the core Java runtime itself.

Java 11 and Beyond

After 8, Java switched to a peculiar numbering system, where new major-version-numbered releases come out every six months, but only the ones that come out every three years are Long-Term-Service releases. As of right now, the current version of Java is 15, but 11 is the active LTS one, and so 11 is effectively the "real" current version for concerns like platform vendors. Java 8 is now in the same spot that Java 6 was for a while, where it's been the baseline expectation for a long time, and it's a slog of a process to move the full community past it.

Still, Java 11 is certainly hitting critical mass now. Eclipse-the-IDE started requiring it in the 2020-09 release, and the various app servers have either supported it for a while or are on the cusp of doing so.

There are a lot of nice things added to the language in the releases past 8, but they've also gotten more aggressive about removing things from the core Java SE runtime, and those changes are the things likely to be immediately noticeable Domino-wise. As I mentioned above, JAX-B was always technically an EE specification, but it was shipped with Java SE for a good long time. As of Java 11, though, it's gone, and instead must be either provided by the app server or brought in as an explicit dependency. The same goes for some less-important packages, such as org.omg - though that package sounds fun, it stands for "Object Management Group" and it just included some classes used for CORBA.

I imagine that few Domino developers use JAX-B or CORBA directly, but our old nemesis Notes.jar sure does! If you're doing any project builds outside of Domino that make use of the Notes.jar API, you likely already have or will soon run into this. For Tycho, I made a patch fragment that provides the required API to the com.ibm.notes.java.api bundle a good while back. For non-Tycho projects, your best bet is generally to include a dependency on the GlassFish-packaged variant and a pre-3.0 version of the Jakarta XML Bind API.

There will be some further removals down the line, like RMI Activation, but I don't think any currently on the horizon will be as pertinent as those.

Java With Domino Roundtable Recording

Nov 17, 2020, 9:37 PM

Tags: java

I hosted my "Java With Domino" roundtable earlier today, and I think it went pretty well! We ended up having just about the ideal number of participants, and it was not only great hearing how people feel on the topic, but also seeing and hearing from everyone.

I've put the video up on YouTube:

I'm thinking of doing more of these, and kind of making them a looser, more-casual companion to OpenNTF's webinar series. I don't know whether they'd all be on similar topics or what, but it seems like it'll be worth continuing.

OpenNTF Fork of p2-maven-plugin

Nov 14, 2020, 6:56 PM

Tags: maven tycho
  1. Converting Tycho Projects to maven-bundle-plugin, Initial Phase
  2. Winter Project #2: Maven P2 Repository Resolver
  3. OpenNTF Fork of p2-maven-plugin
  4. The Intricate Work of OSGi Dependencies on Domino

It's been one of my long-running goals to reduce my use of Tycho for my work. While Tycho does what it says on the tin, the way PDE works in Eclipse means it's an ongoing nightmare to deal with when I want to do simple things like add a new dependency. This isn't really Tycho's fault as such, and the project itself is making major steps to alleviate some issues, but it's the nature of the surrounding tooling. Even beyond that, the shaky support in IntelliJ and total lack of support in Visual Studio Code and similar editors makes it a real thorn in my side.

Still, though, it brings a lot to the table, particularly when dealing with Domino-targeted projects. Because Domino's OSGi layout is... fiddly, it's often safest to use the "Manifest-first" approach for dependencies, and it's definitely important to still be able to do feature projects and p2 repositories for importing into Designer and Domino.

But I've still been trying to whittle away at the constraints over time, and I got fed up enough yesterday to make some major strides.

The Original Project

One of the major tools in my toolbelt for years has been the p2-maven-plugin, which does a lot of heavy lifting when it comes to taking non-Tycho or non-OSGi-focused projects and making them palatable for an OSGi environment. Even when I don't use it as the backbone of a project, I tend to use it to gather third-party dependencies and process them to make them Domino-friendly.

The Fork

It has its limitations, though, that have kept me from using it to replace the final steps of a Tycho build, and those are the ones that I set out to improve. Yesterday, I forked the project and got to work. Most of my work centered around letting it pull more information out of existing p2 repositories. While it already has some knowledge of such repos, it was still geared heavily towards only using them to pick up a bundle here or there. The big annoyance for me there was that I wanted to bring in entire existing p2-housed features into the final update site.

For example, one of my big projects consumes and redistributes a bunch of upstream projects, such as ODA and the XPages Jakarta EE support. While the p2-maven-plugin made it possible to reference those projects as Maven artifacts or individual bundles, I couldn't do what I wanted and just say "bring X and Y features in, including all their bundles".

I also went in and added a few other niceties needed for Domino: generation of the antiquated "site.xml" file for the NSF Update Site, archiving of the final site for distribution, and so forth.

The Implications

With my changes, I was able to delete all of the feature projects in the tree, which lowers the mental complexity a bit. That also means that the only parts "controlled" by Tycho now are the actual bundle projects, and those have a clear path to de-Tycho-ization. Though doing that will make it a little more difficult to know when dependencies are Domino-suitable ahead of time, the conversion should save a ton of hassle overall.

So now, I have a toolchain that should be able to work together to replace Tycho while still working with the Equinox-heavy target:

  • maven-bundle-plugin to generate the OSGi metadata in META-INF/MANIFEST.MF. I could also use bnd-maven-plugin directly for this and bndtools in Eclipse, but I'm not sure that it'd gain me much in practice
  • generate-domino-update-site to create p2 repositories from post-9.0.1 Domino releases' XPages framework, which remains damnably non-Mavenized
  • p2-layout-provider to resolve p2-housed artifacts like those from above and OpenNTF projects and make them available as normal-enough Maven dependencies on the fly
  • The forked p2-maven-plugin to generate features and update sites, as well as to repackage existing bundles to be more Domino-friendly

What's missing now is an ability to run compile-time test suites in a true Equinox environment. I'm hemming and hawing on how important that really is, though. The tests I write only rarely expect the presence of OSGi - the main way it comes into play is for extensions, which are papered over by IBM Commons anyway. I've had a delightful time lately running tests of JAX-RS resources with Liberty's dev mode, and I'm pretty sure I saw some examples somewhere of building up and tearing down a scaffolding to run them during compilation, so maybe I'll switch to that anyway.

In any event, just having a tool to do this stuff is a huge weight off my back, and now the goal of a fully-normal-enough Maven project tree is tantalizingly in sight.

Upcoming Event: Java With Domino Roundtable

Nov 12, 2020, 8:31 PM

Tags: java

The other day, I floated the idea of running an unstructured roundtable discussion of working with Java either on or accessing Domino, and I think it'll be worth giving a shot.

Since Java with Domino is in a weird place, the goal would be to discuss the various ways that people are or want to use it. So that can include XPages, OSGi, REST services generally, Jakarta EE, Spring, Vert.x, and so forth. I'd also like it to be open generally. I imagine I'll have some preliminary remarks, but otherwise the goal is to be less like a webinar and more like a free-flowing discussion, in the vein of the "happy hour" and "coffee break" rooms from CollabSphere and Digital Week.

My current plan is to run it on short notice, next week:

Tuesday, November 17th
2:00 PM US Eastern (19:00 UTC)
https://zoom.us/j/99514285138
Password: Computers!

I'll share the password I come up with on Twitter on the day of the event, so look for it there.