title: Jenkins Git userContent plugin
body: <p>I recently tried to install the <a href="https://wiki.jenkins-ci.org/display/JENKINS/Git+userContent+plugin" rel="noreferrer">Git userContent plugin</a> on Jenkins 1.546. After restarting Jenkins the following error occured:</p>
  
  <pre><code>hudson.util.HudsonFailedToLoad: org.jvnet.hudson.reactor.ReactorException: java.lang.Error: java.lang.reflect.InvocationTargetException
      at hudson.WebAppMain$3.run(WebAppMain.java:234)
  Caused by: org.jvnet.hudson.reactor.ReactorException: java.lang.Error: java.lang.reflect.InvocationTargetException
      at org.jvnet.hudson.reactor.Reactor.execute(Reactor.java:269)
      at jenkins.InitReactorRunner.run(InitReactorRunner.java:44)
      at jenkins.model.Jenkins.executeReactor(Jenkins.java:908)
      at jenkins.model.Jenkins.&lt;init&gt;(Jenkins.java:807)
      at hudson.model.Hudson.&lt;init&gt;(Hudson.java:82)
      at hudson.model.Hudson.&lt;init&gt;(Hudson.java:78)
      at hudson.WebAppMain$3.run(WebAppMain.java:222)
  Caused by: java.lang.Error: java.lang.reflect.InvocationTargetException
      at hudson.init.TaskMethodFinder.invoke(TaskMethodFinder.java:109)
      at hudson.init.TaskMethodFinder$TaskImpl.run(TaskMethodFinder.java:169)
      at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:282)
      at jenkins.model.Jenkins$7.runTask(Jenkins.java:897)
      at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:210)
      at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:117)
      at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
      at java.lang.Thread.run(Unknown Source)
  Caused by: java.lang.reflect.InvocationTargetException
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
      at java.lang.reflect.Method.invoke(Unknown Source)
      at hudson.init.TaskMethodFinder.invoke(TaskMethodFinder.java:105)
      ... 8 more
  Caused by: java.lang.NullPointerException
      at hudson.plugins.git.GitSCM.onLoaded(GitSCM.java:1389)
      ... 13 more
  </code></pre>
  
  <p>I tried reverting to Jenkins 1.544 via the <b>jenkins.war.bak</b>, but the error persists. I can not access Jenkins anymore. Is there any way to recover from this, or at least a decent way to re-install Jenkins without losing any data?</p>