我试图为Jenkins安装ruby-runtime（0.12）插件，但收到以下错误：
ruby-runtime
Failure -
java.lang.NullPointerException
at java.lang.Class.isAssignableFrom(Native Method)
at org.jenkinsci.jruby.JavaProxyConverter.canConvert(JavaProxyConverter.java:43)
at com.thoughtworks.xstream.core.DefaultConverterLookup.registerConverter(DefaultConverterLookup.java:74)
at com.thoughtworks.xstream.XStream$2.registerConverter(XStream.java:502)
at com.thoughtworks.xstream.XStream.registerConverter(XStream.java:1422)
at com.thoughtworks.xstream.XStream.registerConverter(XStream.java:1417)
at org.jenkinsci.jruby.JRubyXStream.register(JRubyXStream.java:26)
at ruby.RubyRuntimePlugin.initRubyXStreams(RubyRuntimePlugin.java:44)
at ruby.RubyRuntimePlugin.start(RubyRuntimePlugin.java:28)
at hudson.ClassicPluginStrategy.startPlugin(ClassicPluginStrategy.java:539)
at hudson.ClassicPluginStrategy.load(ClassicPluginStrategy.java:528)
Caused: java.io.IOException: Failed to initialize
at hudson.ClassicPluginStrategy.load(ClassicPluginStrategy.java:531)
at hudson.PluginManager.dynamicLoad(PluginManager.java:872)
Caused: java.io.IOException: Failed to install ruby-runtime plugin
at hudson.PluginManager.dynamicLoad(PluginManager.java:881)
at hudson.PluginManager.dynamicLoad(PluginManager.java:820)
at hudson.model.UpdateCenter$InstallationJob._run(UpdateCenter.java:1889)
Caused: java.io.IOException: Failed to dynamically deploy this plugin
at hudson.model.UpdateCenter$InstallationJob._run(UpdateCenter.java:1893)
at hudson.model.UpdateCenter$DownloadJob.run(UpdateCenter.java:1651)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at hudson.remoting.AtmostOneThreadExecutor$Worker.run(AtmostOneThreadExecutor.java:110)
at java.lang.Thread.run(Thread.java:748)
我在类似问题上发现了一些问题，但是他们似乎都没有解决这个具体问题。非常感谢任何帮助或在故障排除方面的进展。