I have Hudson v2.20 installed. I am trying to install the FindBugs plugin, but when Hudson restarts after downloading the plugin, the plugin fails to load with the following error below. Has anyone else seen this? And if so, how would I solve it?

I installed the plugin using the Hudson plugin interface. My guess is that the plugin is incompatible with the Hudson version for some reason?

```
hudson.util.IOException2: Failed to load plugin instance for: analysis-core
    at org.hudsonci.inject.internal.plugin.SmoothiePluginStrategy.load(SmoothiePluginStrategy.java:193)
    at org.hudsonci.inject.internal.plugin.DelegatingPluginStrategy.load(DelegatingPluginStrategy.java:72)
    at hudson.PluginManager$2$1$1.run(PluginManager.java:297)
    at org.jvnet.hudson.reactor.TaskGraphBuilder$TaskImpl.run(TaskGraphBuilder.java:146)
    at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:259)
    at hudson.model.Hudson$4.runTask(Hudson.java:698)
    at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:187)
    at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:94)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.LinkageError: loader (instance of  org/hudsonci/inject/internal/plugin/PluginClassLoader): attempted  duplicate class definition for name: "org/apache/xerces/parsers/SAXParser"
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:465)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:139)
    at org.aspectj.weaver.bcel.ExtensibleURLClassLoader.defineClass(ExtensibleURLClassLoader.java:63)
    at org.aspectj.weaver.loadtime.WeavingURLClassLoader.defineClass(WeavingURLClassLoader.java:151)
    at org.aspectj.weaver.bcel.ExtensibleURLClassLoader.defineClass(ExtensibleURLClassLoader.java:97)
    at org.aspectj.weaver.bcel.ExtensibleURLClassLoader.findClass(ExtensibleURLClassLoader.java:52)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    at hudson.ClassicPluginStrategy$DependencyClassLoader.findClass(ClassicPluginStrategy.java:426)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:295)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    at org.xml.sax.helpers.NewInstance.newInstance(NewInstance.java:49)
    at org.xml.sax.helpers.XMLReaderFactory.loadClass(XMLReaderFactory.java:187)
    at org.xml.sax.helpers.XMLReaderFactory.createXMLReader(XMLReaderFactory.java:150)
    at org.aspectj.weaver.loadtime.definition.DocumentParser.getXMLReader(DocumentParser.java:167)
    at org.aspectj.weaver.loadtime.definition.DocumentParser.saxParsing(DocumentParser.java:137)
    at org.aspectj.weaver.loadtime.definition.DocumentParser.parse(DocumentParser.java:117)
    at org.aspectj.weaver.loadtime.ClassLoaderWeavingAdaptor.parseDefinitions(ClassLoaderWeavingAdaptor.java:258)
    at org.aspectj.weaver.loadtime.DefaultWeavingContext.getDefinitions(DefaultWeavingContext.java:130)
    at org.aspectj.weaver.loadtime.ClassLoaderWeavingAdaptor.initialize(ClassLoaderWeavingAdaptor.java:161)
    at org.aspectj.weaver.loadtime.WeavingURLClassLoader.createAdaptor(WeavingURLClassLoader.java:171)
    at org.aspectj.weaver.loadtime.WeavingURLClassLoader.defineClass(WeavingURLClassLoader.java:132)
    at org.aspectj.weaver.bcel.ExtensibleURLClassLoader.defineClass(ExtensibleURLClassLoader.java:97)
    at org.aspectj.weaver.bcel.ExtensibleURLClassLoader.findClass(ExtensibleURLClassLoader.java:52)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    at org.hudsonci.inject.internal.plugin.SmoothiePluginStrategy.loadPluginClass(SmoothiePluginStrategy.java:217)
    at org.hudsonci.inject.internal.plugin.SmoothiePluginStrategy.load(SmoothiePluginStrategy.java:188)
    ... 10 more

```