We're have released jruby-rack 2.0.0, updating our servlet/rack bridge to the Jakarta Servlet API! We partnered with JRuby contributor Chad Wilson (github.com/chadlwilson) and the Kill Bill (killbill.io) Open Source billing and payments platform to make this happen. github.com/jruby/jruby-...

Release 2.0.0 · jruby/jruby-rack

What's Changed Major breaking changes: Support Jakarta Servlet API 5.0 → 6.1 (Jakarta EE 9 → 11) (@chadlwilson & @bhagyashriSawkar) This release involves migration to the jakarta.servlet.* namesp...

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I will actually speak at @xoruby.com in NYC this SATURDAY, October 10th, at the Metropolitan Pavilion! XO Ruby events are focused on local Ruby communities, with a dirt cheap, one day, single track setup. Stop by and let's chat about JRuby! buff.ly/fKA2EMQ

New York City

Bagels. Bodegas. Big Ruby Energy.

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I don't read code to make the code better. I read code to make myself better. I understand the system better by reading the code, which makes me better at creating new code.

I'm looking forward to "stop writing code" and "stop reading code" to evolve into "stop running code" and we just revert back to an agrarian society.

Things I want from GitHub: * Align Milestones, Releases, and Tags in a logical way. Multiple Milestones per issue/PR. * A button to enter review mode on front page of PR. * A list of "Changes Requested" (current indicator is useless). * Re-run single job directly from the front PR page.

There's a big difference between "implement this app/feature" and low-level optimizations, refactorings, or memory/thread-safety improvements. The former is "easy" for AI, but the latter is less narrowly-scoped and more sensitive to complexity. In my experience, that requires a lot of intervention.

I've pushed a Rails 8.1-compatible activerecord-jdbc-adapter 81.0.pre1 for JRuby + SQLite and it can at least CRUD a scaffold app! I've provided a template here for generating a new app: (rails new -m <template>) buff.ly/uUPEfJn

"Eclipse Collections Categorically" is a thinking book. What if you could tell your data structures to do work for you? What categories of things would you ask for? 🤷‍♂️👇 *Note*: $0 to buy Amazon Kindle version for few more hours. Search title on website, not mobile. donraab.medium.com/my-ten-year-...

Top three questions I got at #railsworld: Q: Does Rails work on JRuby? A: Yes, for 20 years now. Q: Didn't JRuby already solve this? A: Yes. Q: Why aren't you speaking here? A: I tried. Ask the organizers.

I'll be hanging out at #railsworld in the hack space near the entry. Come on over to chat about JRuby, or claim a shirt if you're a current user or supporter!

Charles Oliver Nutter@headius.bsky.social · 2w ago

Calling all JRubyists at #railsworld! I HAVE T-SHIRTS! If you are using JRuby or officially support it in your app or library, come find me Thursday! I have L, XL, and one 3XL left.

Very interesting day of discussions at #railsworld! Introduced a few folks to JRuby, talked with some current users I did not know, even found one shop that only does JRuby. A bit sad to see folks struggling with problems JRuby solves. Hard to get the word out!

Calling all JRubyists at #railsworld! I HAVE T-SHIRTS! If you are using JRuby or officially support it in your app or library, come find me Thursday! I have L, XL, and one 3XL left.

Yeah, I don't get why not just let this be CRuby's weakness. If you can't get rid of the GVL – which is understandable as even in Python it's still opt-in – then accept that and promote alternative solutions. I don't see how this level of restriction is ever going to work in practice 🤷‍♂️

Hello #railsworld! I'm here at the event running office hours and teaching people how to run Rails on JRuby. Find me in the vendor pavilion and grab a sticker!

It's incredible the amount of hacking required to get Rails to run in parallel with Ractors (and it still isn't there yet) when JRuby has been running Rails in parallel for decades. #railsworld

Hello JRubyists! Anyone planning to be at tiny ruby #{conf} 2026 presented by @helsinkiruby.fi next week? We'd love to help you spread the word about JRuby to the Helsinki Ruby community! Get in touch if we can help you in any way!

It occurs to me now: with the JVM now supporting native function calls and memory via the FFM API, could we not potentially treat it as a C compiler backend?

Would you buy JRuby swag to help fund the project? We recently did a run of JRuby "bird" t-shirts that have been very popular, but that stuff is expensive to give away for a little startup like ours.

Brno is a lovely little city. Don't know why I didn't see it when I visited in 2012.

It's amazing how quickly the toxic AI bros come out on X if you say one bad word about AI. Are they even real people?

I think I'm going to enable the JVM vector API (SSE etc, we already ship some optimizations that use it) by default for JRuby. Convince me not to.

After all these years, I just got burned (almost) by having a CI job not actually fail when one of the steps failed. It involved a subprocess launch with no error check, so even if it bombed out the job stayed green. 😩 A friendly reminder to make sure your CI jobs actually *can* fail.

Slides from my Euruko 2026 talk "JRuby: Past, Present, and Future" are now uploaded. I believe the talks were also recorded, so hopefully video will follow soon. Great event, I hope to return for 2027 in Modena, Italy! buff.ly/paSd5t9

JRuby: Past, Present, and Future

JRuby on Rails is 20 years old! This talk reviews the last 20 years of JRuby development, with a focus on the challenges of supporting Ruby and Rails ye…

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AI is now the largest single point of failure in the history of software development. I know tons of developers that can't even work without an agent now. It's shocking how quickly the industry has become totally dependent on a few companies' services.

I'm finding more and more that agent-driven developers *really* appreciate having a human validate what they submit. nobody wants to be the asshole in an OSS project and being honest and communicative goes a long way toward making a good patch.

Like clockwork, I go to a Ruby event and meet JRuby users I never knew about! Just today, three people who used JRuby at previous jobs and two more that currently have apps in production. Gotta figure out how to reach these folks without speaking at every Ruby conference! 🤣

Interested in Ruby::Box? Use JRuby and you already have it! These are fully-isolated, fully-parallel JRuby VMs running in the same process. Here's a simple example from my Euruko 2026 talk. Let's work together to make Box work on ALL Rubies!

Feels nice to be back in Czechia! I'm currently transiting from Prague to Brno for Euruko 2026. I think the last time I visited was almost 14 years ago, shortly after first joining Red Hat. I have a free day before and after the conference so I'm hoping to do a bit of touring.

My own experiments using AI for JRuby work have been mixed, but I can report a great success: contributions from people that never would have attempted such things before, like Ruby core devs and Rubyists with no JVM experience. So many PRs lately! github.com/jruby/jruby

GitHub · Change is constant. GitHub keeps you ahead.

Join the world's most widely adopted, AI-powered developer platform where millions of developers, businesses, and the largest open source community build software that advances humanity.

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Last call: EuRuKo 2026 tickets close tomorrow at midnight CEST. @matz.bsky.social opening, @ko1s.bsky.social closing, @headius.bsky.social on JRuby. Brno, Sept 17–18. After tomorrow there's no late registration. 2026.euruko.org