JRuby 1.2 RC1 has been released (JRuby 1.2 RC1 Download). JRuby 1.2 is a maintenance release, but it marks the switch to a slightly different versioning scheme, ie. future maintenance releases will change the x in 1.x.
JRuby 1.2 contains a large number of bug fixes, result of a major cleanup of the JRuby JIRA bug database.
The release also comes with improvements to compatibility with both Ruby 1.8 and Ruby 1.9, from the release notes:
- Improved Ruby 1.9 support (via --1.9)
- Compiler now works
- Almost all of the missing 1.9 methods have been added
The performance has also been improved in many areas, again from the release notes:
- New experimental --fast flag which does more aggressive optimizations
- Large scale compiler and runtime cleanup and performance audit
- Parsing is 3-6x faster now.
The 1.2 release also contains the beginnings of a long awaited feature: JRuby on Android. Some of the changes can be seen in a commit, which fixes some compatibility issues.
The Android support also seems to use only JRuby interpretation and not JIT compilation (compilation of Ruby source to Java bytecodes), as can be seen by the command shown on Charles Nutter's blog, where he uses this to run JRuby on Android:
dalvikvm -classpath ruboto.jar org.jruby.Main -X-C test.rb
The "-X-C" flag turns off JRuby's JIT compilation.
The availability of JRuby on Android might help change the situation of Ruby on mobile devices. Rhodes is a Ruby-based framework which already brings Ruby to the iPhone, Symbian and Windows Mobile, as well as to Java-based devices like the Blackberry, with Android support planned for one of the next releases.
Finally, the current JRuby release is the first release candidate for the 1.2 release - this means, now is the time to report regressions or problems that should be fixed for the final 1.2 release.