JRuby 10.1.2.0 is released! JRuby 10.1 is our edge line, with more aggressive performance work and refactorings. This release improves perf of Ruby classes that extend Java, startup time on MacOS, and includes many stdlib updates. jruby.org/2026/09/21/jruby-1…

JRuby 10.0.7.0 is released! JRuby 10.0 is our stable line, receiving only bug and security fixes and critical performance improvements. This release tidies up another round of compatibility issues and updates a few standard libraries. jruby.org/2026/09/21/jruby-1…

Hello JRubyists! Anyone planning to be at tiny ruby #{conf} 2026 in Helsinki 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!

JRuby 10.1.1.0 is released, with a bunch of compat fixes, more performance work, and several third-party CVEs resolved. JRuby 10.1 is our active development branch, with 10.0 being stable. Upgrading is recommended if you want the latest and greatest! jruby.org/2026/07/22/jruby-1…

Our friends over at @fastrubyio have posted a nice compatibility matrix for JRuby versions, covering Ruby and Rails versions. Check it out to see how the versions line up or to learn how JRuby can help you run Ruby and Rails better! fastruby.io/blog/jruby/rails…

JRuby 10.0.6.0 released! Updated jruby-openssl, faster Java interface support, and many other fixes and improvements. JRuby 10.0.x is our LTS version, so upgrading is recommended. jruby.org/2026/06/11/jruby-1…

JRuby 9.4.15.0 is released! This is the last regularly-scheduled release of JRuby 9.4.x and includes the last set of 9.4 fixes. Future releases will be done as needed for commercial JRuby users. Contact us if you need long-term JRuby 9.4 support. jruby.org/2026/06/08/jruby-9…

JRuby 10.1 is released! We've caught up with CRuby 4.0 after less than four months, and pushed a bunch of new optimizations: smaller objects, smaller numerics, and groundwork for many more. We'll maintain 10.0 as our stable line, but do try 10.1 yourself! jruby.org/2026/04/21/jruby-1…

JRuby 10.0.5.0 is released! This round we fixed some memory leaks when embedding multiple JRuby instances, a few pesky Windows bugs, and several Ruby compatibility blockers. Enjoy! jruby.org/2026/04/06/jruby-1…

Today we were informed of a low-severity vulnerability in the bcrypt-ruby gem. We worked with the maintainers to arrange a fix. Upgrading is recommended. CVE-2026-33306: Integer Overflow Causes Zero Key-Strengthening Iterations at Cost=31 on JRuby github.com/bcrypt-ruby/bcryp…

JRuby 10.0.4.0 is released! A month after 10.0.3.0, we've addressed lots of one-off issues, a few memory and thread-safety fixes, and general compatibility and stabilization work. Enjoy! jruby.org/2026/03/04/jruby-1…

JRuby 10.0.3.0 is released! Over 80 issues and pull requests and 13 external contributors combined to help further stabilize our 10.0 series! There's lots of compatibility fixes, a few performance enhancements, and a number of library updates. jruby.org/2026/02/02/jruby-1…

Warbler 2.1.0 has been released! Warbler allows you to package JRuby applications (with obfuscation of code) as a single binary, either a .jar file you can run directly or a .war file you can deploy to any Java application server. Blog post coming! rubygems.org/gems/warbler/ve…

We have published Docker images for JRuby 9.4 and JRuby 10 on JDK 25! The -dev images are also updated to latest commits. Give them a try and let us know if there's any issues!

JRuby 9.4.14.0 is released! We've updated a bunch of the standard library (including "cgi" to fix a couple of CVEs), fixed a few memory leaks and a bunch of compatibility issues, and generally stabilized things. Upgrading is recommended! jruby.org/2025/08/28/jruby-9…

JRuby 10.0.2.0 is released! This is a small release to fix an ArgumentError regression in JRuby 10.0.1.0 plus a few other small fixes. Recommended upgrade for all, but let us know if you run into any issues! jruby.org/2025/08/07/jruby-1…

We have just released JRuby 10.0.1.0, our first update to JRuby 10! There's dozens of patches including full support (finally) for Zeitwerk and a bunch of Ruby 3.4 language fixes. Upgrade today and let us know how it goes! jruby.org/2025/07/17/jruby-1…

We have released jruby-maven-plugins 3.0.6, updating JRuby to 9.4.13.0 along with several other improvements. But more exciting: Warbler is BACK! We've updated it for latest JRuby and dependencies and it's running green in CI. Time for feature requests! github.com/jruby/warbler/iss…

FYI: now that Ubuntu 20.04 is EOL, future releases of the JRuby Docker image will be based on Ubuntu 22.04. This will take effect with releases 9.4.14.0 and 10.0.1.0, whenever they happen. See github.com/docker-library/of…

JRuby 9.4.13.0 is released! We have fixed several user issues, including a slow leak in Java interface implementation, a possible deadlock between JIT and main threads, and backported launcher improvements from JRuby 10! jruby.org/2025/06/10/jruby-9…