Java, Ruby, and JVM guy trying to make sense of it all
This year marks a big milestone in my history working on JRuby: twenty years ago, I joined Sun Microsystems to work on the project full-time. This month also marks another milestone for JRuby: two years being independently funded by my company Headius Enterprises through commercial support contracts. It’s a perfect time for us to return to RubyConf 2026 and show today’s Rubyists what JRuby can do…
Ever since JRuby 10 upgraded to Java 21, I’ve been re-learning Java with all the excellent language enhancements of the past decade. One of my favorites has to be the instanceof pattern matching features added in Java 16. Today I also realized I can use an instanceof pattern to null-check and assign a variable at the same time.
In my previous post, I showed how to use Warbler to package a simple image-processing tool as an executable jar. This post will demonstrate how to “warble” a larger project: the Sidekiq background job server!
Warbler is the JRuby ecosystem’s tool for packaging up Ruby apps with all dependencies in a single deployable file. We’ve just released an update, so let’s explore how to use Warbler to create all-in-one packaged Ruby apps!
Java 9 added the ability to mark a @Deprecated annotation with a “since” version, so we figured it was worth updating JRuby.
At the end of my post on JRuby and JDK 25 startup time features, I teased a bit of the unreleased improvements from Project Leyden. It turns out the latest commits improve startup time even more, so it seems worth posting a quick follow-up!
JDK 25 is the newest LTS release since JDK 21, and it ships with a gaggle of amazing VM-level features. This post will cover one of the most important improvements for command-line ecosystems like JRuby’s: the AOTCache (ahead-of-time cache) and its ability to pre-optimize code for future runs.
After playing with JFreeChart and JRuby and writing up a lovely blog post called “Beautiful Charts with JRuby and JFreeChart” it seems that some folks did not agree with my assessment of the charts as “beautiful” and others did not realize the power of what they’d just seen.
I recently returned from RubyKaigi where I had the opportunity to sit down with members of the Japanese Ruby community and show them a little bit of JRuby. One of the items that came up a few times was the difficulty of utilizing external libraries from Ruby: if it’s a C library, typically you have to either write a C extension or do the extra work of writing up an FFI binding.
I am very excited to introduce you to JRuby 10, our biggest leap forward since “JRuby 9000” was released almost a decade ago.