JRuby is the effort to recreate the Ruby interpreter in Java. JRuby is tightly integrated with Java to allow both to script any Java class and to embed the interpreter into any Java application.
Information regarding Project Releases and Project Resources. Note that the information here is a quote from Freecode.com page, and the downloads themselves may not be hosted on OSDN.
Overall performance is 50-60% faster than 0.9.0. Improved Rails support. A new syntax for including Java classes into Ruby. A new interpreter design. Refactoring of the method dispatch, code evaluation, and block dispatch code. Parser performance enhancements. Rewriting of Enumerable and StringScanner in Java. New experimental syntax for implementing interfaces. 86 Jira issues have been resolved since 0.9.0.
Many bugs have been fixed. RubyGems 0.9.0 is now
installed and working. WEBrick runs. Ruby on Rails
runs on top of WEBrick (and generation scripts
work). The YAML parser was much improved. All
non-native standard libraries are bundled in the
distribution. Correctness is now approaching a
level that is sufficient to run the more
complicated Ruby libraries and applications
properly.
This version fixes a huge number of problems. irb
now works. Included Java classes are dramatically
faster to load and use. Binding works. Every known
constant scoping issue has been fixed. Interpreter
redesign work has resulted in improved stack depth
and advances the effort to support continuations.
A serious concurrency error when Ruby instances
are passed back out to Java was fixed. Java
classes can be adorned with Ruby methods via the
extend_proxy method.
This release has full support for Ruby 1.8.x grammar (previously a mix of 1.6 and 1.8). It runs the RubyForge rubicon test suite (though not all tests pass). Almost a countless number of core class/module fixes. Improved Java integration support. Threading has been greatly improved. Now tri-licensed under the CPL/GPL/LGPL.
