我试图更新几个我的jenkins插件（不记得是哪个），但是被挂了。大约15分钟后，我决定重新启动jenkins服务器。这是我在詹金斯UI上得到的：

org.jvnet.hudson.reactor.ReactorException: java.lang.Error: java.lang.reflect.InvocationTargetException
    at org.jvnet.hudson.reactor.Reactor.execute(Reactor.java:246)
    at jenkins.InitReactorRunner.run(InitReactorRunner.java:43)
    at jenkins.model.Jenkins.executeReactor(Jenkins.java:894)
    at jenkins.model.Jenkins.<init>(Jenkins.java:796)
    at hudson.model.Hudson.<init>(Hudson.java:81)
    at hudson.model.Hudson.<init>(Hudson.java:77)
    at hudson.WebAppMain$2.run(WebAppMain.java:214)
Caused by: java.lang.Error: java.lang.reflect.InvocationTargetException
    at hudson.init.InitializerFinder.invoke(InitializerFinder.java:124)
    at hudson.init.InitializerFinder$TaskImpl.run(InitializerFinder.java:184)
    at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:259)
    at jenkins.model.Jenkins$7.runTask(Jenkins.java:883)
    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.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at hudson.init.InitializerFinder.invoke(InitializerFinder.java:120)
    ... 8 more
Caused by: java.lang.NoClassDefFoundError: hudson/PluginManager$PluginUpdateMonitor
    at hudson.maven.PluginImpl.init(PluginImpl.java:54)
    ... 13 more
Caused by: java.lang.ClassNotFoundException: hudson.PluginManager$PluginUpdateMonitor
    at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    ... 14 more

我试图将战争从1.486更新为1.502，但行为没有变化。如何使Jenkins重新运作？