The JRuby community is pleased to announce the release of JRuby 9.4.15.0. - Homepage: https://www.jruby.org/ - Download: https://www.jruby.org/download JRuby 9.4.15.x targets Ruby 3.4 compatibility. Thank you to our contributors this release, you help keep JRuby moving forward! With this release, JRuby 9.4 moves into end-of-life (“EOL”). This means that future releases of 9.4.x will only be provided as needed by commercial JRuby users. Get in touch with us if you require long-term support options for the JRuby 9.4.x series. 38 Issues and PRs resolved for 9.4.15.0 - #8801 ruby/logger gem broken after version 1.6.3 using JRuby on Windows <https://github.com/jruby/jruby/issues/8801> - #8924 const_defined? returns false for External Constants in JRuby 10.0.1.0 and 9.4.14.0 <https://github.com/jruby/jruby/issues/8924> - #8974 Use RuboCop to clean up poms (9.4) <https://github.com/jruby/jruby/pull/8974> - #8990 Launcher defensive fixes 9.4 <https://github.com/jruby/jruby/pull/8990> - #9000 JRuby 9.4.14.0 “wrong number of arguments” when jit.threshold=0 <https://github.com/jruby/jruby/issues/9000> - #9001 Backport indy ruby2_keywords ArgumentError fix <https://github.com/jruby/jruby/pull/9001> - #9002 Backport ArgumentError message update from 2010 <https://github.com/jruby/jruby/pull/9002> - #9012 Rexml security updateUpdate rexml gem to solve CVE-2025-58767 (9.4) <https://github.com/jruby/jruby/pull/9012> - #9030 Official JDK 25 support for JRuby 9.4 <https://github.com/jruby/jruby/pull/9030> - #9031 Don’t restrict object search to modules <https://github.com/jruby/jruby/pull/9031> - #9032 Different arguments for each.map vs each and map alone <https://github.com/jruby/jruby/issues/9032> - #9033 Backport jruby.sh and .jruby.release changes from 10 <https://github.com/jruby/jruby/pull/9033> - #9037 fix: clear code-range when re-using a string buffer (#9035) <https://github.com/jruby/jruby/pull/9037> - #9044 Difference in Float() hex parsing between JRuby and CRuby <https://github.com/jruby/jruby/issues/9044> - #9045 Fixes basic float hex value strings for Kernel#Float <https://github.com/jruby/jruby/pull/9045> - #9054 Migrate .java-version contents to .jruby.release (9.4) <https://github.com/jruby/jruby/pull/9054> - #9104 [9.4] Update jruby-openssl to v0.15.5 to resolve BouncyCastle 1.79 vulnerability (sonatype-2025-001911). <https://github.com/jruby/jruby/issues/9104> - #9105 [9.4] Update jruby-openssl to 0.15.5 <https://github.com/jruby/jruby/pull/9105> - #9128 [9.4] fix(launcher): correct parsing of java release files under Bash/msys2 etc on Windows <https://github.com/jruby/jruby/pull/9128> - #9160 Update strscan to 3.1.7 <https://github.com/jruby/jruby/pull/9160> - #9186 9032 Fix Different arguments for each.map vs each and map alone <https://github.com/jruby/jruby/pull/9186> - #9201 Extract float formatting into a static method (9.4) <https://github.com/jruby/jruby/pull/9201> - #9295 Issue with calling IO.popen(env, cmd, opts) on Windows <https://github.com/jruby/jruby/issues/9295> - #9308 Process.detach raises ArrayIndexOutOfBoundsException if called from a thread that is not the main thread <https://github.com/jruby/jruby/issues/9308> - #9311 Push a frame for thread toplevel <https://github.com/jruby/jruby/pull/9311> - #9347 Use JDK for File#flock on Windows <https://github.com/jruby/jruby/pull/9347> - #9351 Fix non-native IO.popen env + kwargs handling <https://github.com/jruby/jruby/pull/9351> - #9353 Update JNR dependencies <https://github.com/jruby/jruby/pull/9353> - #9377 Checking out aws-sdk-ruby creates a file with binary data. <https://github.com/jruby/jruby/issues/9377> - #9387 [9.4] deps(stdlib): bump erb from 2.2.3 to 4.0.4.1 to resolve CVE-2026-41316 <https://github.com/jruby/jruby/pull/9387> - #9391 [9.4] [deps] bump jruby-openssl to 0.16.0 <https://github.com/jruby/jruby/pull/9391> - #9415 Don’t read or write anything once length is zero <https://github.com/jruby/jruby/pull/9415> - #9443 JRuby 9.4 does not generate bytecode for newer JDK versions <https://github.com/jruby/jruby/issues/9443> - #9444 Allow bytecode version to be open-ended <https://github.com/jruby/jruby/pull/9444> - #9464 [fix] escape shell metachars in chdir: to prevent injection <https://github.com/jruby/jruby/pull/9464> - #9467 [9.4] backport [ji] support java.lang.Throwable#backtrace_locations (#9461) <https://github.com/jruby/jruby/pull/9467> - #9477 Dist verification 9.4 <https://github.com/jruby/jruby/pull/9477> - #9480 [fix] @JRubyMethod error with required>=1 and var-args <https://github.com/jruby/jruby/pull/9480> *Charles Oliver Nutter* *Architect and Technologist* Headius Enterprises https://www.headius.com headius@headius.com