JRuby bundled tzdata doesn't contain recent changes to time zones in Russia, so Time.now works incorrectly:

In 14:57 MSK:

» jruby -e 'puts Time.now'                                                                                                 
2014-10-27 15:57:33 +0400`

To fix the issue JRuby needs to update bundled joda-time to 2.5, which contains correct tzdata rules.

» JRUBY_CP=joda-time-2.5.jar jruby -e 'puts Time.now'
2014-10-27 14:57:37 +0300

For now we are using JRUBY_CP variable as temporary workaround, but it only work with bash-based jruby launcher, not native one.