INFO: Starting the installation of Ruby Runtime Plugin on behalf of andrea
Oct 28, 2015 8:49:00 AM hudson.model.UpdateCenter$UpdateCenterConfiguration download
INFO: Downloading Ruby Runtime Plugin
Oct 28, 2015 8:49:01 AM hudson.PluginManager dynamicLoad
INFO: Attempting to dynamic load /var/lib/jenkins/plugins/ruby-runtime.jpi
Oct 28, 2015 8:49:02 AM ruby.RubyRuntimePlugin start
INFO: Injecting JRuby into XStream
Oct 28, 2015 8:49:02 AM hudson.model.UpdateCenter$DownloadJob run
SEVERE: Failed to install Ruby Runtime Plugin
java.io.IOException: Failed to dynamically deploy this plugin
	at hudson.model.UpdateCenter$InstallationJob._run(UpdateCenter.java:1328)
	at hudson.model.UpdateCenter$DownloadJob.run(UpdateCenter.java:1126)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at hudson.remoting.AtmostOneThreadExecutor$Worker.run(AtmostOneThreadExecutor.java:110)
	at java.lang.Thread.run(Thread.java:744)
Caused by: java.io.IOException: Failed to install ruby-runtime plugin
	at hudson.PluginManager.dynamicLoad(PluginManager.java:487)
	at hudson.model.UpdateCenter$InstallationJob._run(UpdateCenter.java:1324)
	... 5 more
Caused by: java.io.IOException: Failed to initialize
	at hudson.ClassicPluginStrategy.load(ClassicPluginStrategy.java:441)
	at hudson.PluginManager.dynamicLoad(PluginManager.java:478)
	... 6 more
Caused by: java.lang.ClassCircularityError: org/jruby/RubyClass
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:270)
	at org.jenkinsci.bytecode.ClassWriter.loadClass(ClassWriter.java:97)
	at org.jenkinsci.bytecode.ClassWriter.getCommonSuperClass(ClassWriter.java:64)
	at org.kohsuke.asm5.ClassWriter.getMergedType(ClassWriter.java:1654)
	at org.kohsuke.asm5.Frame.merge(Frame.java:1426)
	at org.kohsuke.asm5.Frame.merge(Frame.java:1374)
	at org.kohsuke.asm5.MethodWriter.visitMaxs(MethodWriter.java:1475)
	at org.kohsuke.asm5.tree.MethodNode.accept(MethodNode.java:833)
	at org.kohsuke.asm5.commons.JSRInlinerAdapter.visitEnd(JSRInlinerAdapter.java:187)
	at org.jenkinsci.bytecode.Transformer$1$1.visitEnd(Transformer.java:107)
	at org.kohsuke.asm5.MethodVisitor.visitEnd(MethodVisitor.java:877)
	at org.kohsuke.asm5.ClassReader.readMethod(ClassReader.java:1021)
	at org.kohsuke.asm5.ClassReader.accept(ClassReader.java:693)
	at org.kohsuke.asm5.ClassReader.accept(ClassReader.java:506)
	at org.jenkinsci.bytecode.Transformer.transform(Transformer.java:113)
	at hudson.ClassicPluginStrategy$AntClassLoader2.defineClassFromData(ClassicPluginStrategy.java:800)
	at jenkins.util.AntClassLoader.getClassFromStream(AntClassLoader.java:1310)
	at jenkins.util.AntClassLoader.findClassInComponents(AntClassLoader.java:1366)
	at jenkins.util.AntClassLoader.findClass(AntClassLoader.java:1326)
	at jenkins.util.AntClassLoader.loadClass(AntClassLoader.java:1079)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
	at org.jenkinsci.jruby.RubyClassConverter.<init>(RubyClassConverter.java:12)
	at org.jenkinsci.jruby.JRubyXStream.register(JRubyXStream.java:25)
	at ruby.RubyRuntimePlugin.initRubyXStreams(RubyRuntimePlugin.java:44)
	at ruby.RubyRuntimePlugin.start(RubyRuntimePlugin.java:28)
	at hudson.ClassicPluginStrategy.startPlugin(ClassicPluginStrategy.java:449)
	at hudson.ClassicPluginStrategy.load(ClassicPluginStrategy.java:438)
	... 7 more