Upgrade JRuby to latest 1.6.7 point release. Motivation: "The primary goal of the 1.6.x series is to round out our 1.9 support by fixing any reported incompatibilities. Of course, as with any JRuby release, we will continue fixing any found incompatibilities and also improve performance. All users of 1.6.6 (and lower) are encouraged to upgrade to 1.6.7." Where 1.7 fits in: 1.6.7 is expected to be the last release in the 1.6.x line before 1.7.0 is released. Therefore, this is a good stopping point for Fedora 17, making Fedora 18 the logical jump to 1.7.0. That decision can be tracked in a separate issue.
For Fedora 17 or 18, this is no longer an option. Hoewever Fedora 19 will ship with JRuby 1.7.2, so I'm closing this bug.