Tested with Yammer Plugin and buddycloud Plugin in Jenkins 2.x. Since Yammer and buddycloud plugins depend on jruby based Ruby Runtime Plugin, installing those installs Ruby Runtime first.
As long as I don't restart Jenkins, the plugins work, and their settings persist. But after Jenkins is restarted the Post-Build Action settings on all job's configuration pages are lost and have to be re-entered. The jobs' respective config.xml files retain correct settings, but they seem to have no effect. Is there a fix or a workaround? thanks