please upgrade the ruby-runtime plugin to include a recent version of JRuby e.g. 1.7.12.
Code changed in jenkins
User: Josh Stupplebeen
[FIXED JENKINS-12094][FIXED JENKINS-23071] Upgrading jRuby version to 1.7.16 fixes both of these issues, [FIXED JENKINS-25782] Replaced ASCII spaces with space characters, removed some unused imports