Every once in a while with Hudson v1.337 we get the following stack trace:

org.apache.commons.jelly.JellyTagException: jar:file:/opt/users/hudsonbuild/.hudson/war/WEB-INF/lib/hudson-core-1.337.jar!/hudson/widgets/HistoryWidget/index.jelly:28:81: method forName threw exception: hudson.model.Job
at org.apache.commons.jelly.tags.core.InvokeStaticTag.doTag(InvokeStaticTag.java:148)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:262)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:186)
at org.apache.commons.jelly.tags.core.ParseTag.parseBody(ParseTag.java:178)
at org.apache.commons.jelly.tags.core.ParseTag.doTag(ParseTag.java:78)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:262)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:186)
at org.apache.commons.jelly.tags.core.JellyTag.doTag(JellyTag.java:45)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:262)
at org.kohsuke.stapler.jelly.IncludeTag.doTag(IncludeTag.java:118)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:262)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:186)
at org.apache.commons.jelly.tags.core.ForEachTag.doTag(ForEachTag.java:150)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:262)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.kohsuke.stapler.jelly.CustomTagLibrary$StaplerDynamicTag$1.run(CustomTagLibrary.java:147)
at org.apache.commons.jelly.tags.define.InvokeBodyTag.doTag(InvokeBodyTag.java:91)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:262)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:186)
at org.apache.commons.jelly.tags.core.IfTag.doTag(IfTag.java:42)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:262)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:186)
at org.apache.commons.jelly.tags.core.JellyTag.doTag(JellyTag.java:45)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:262)
at org.apache.commons.jelly.impl.DynamicTag.doTag(DynamicTag.java:81)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:262)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:186)
at org.apache.commons.jelly.tags.core.JellyTag.doTag(JellyTag.java:45)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:262)
at org.kohsuke.stapler.jelly.IncludeTag.doTag(IncludeTag.java:118)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:262)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.kohsuke.stapler.jelly.CustomTagLibrary$StaplerDynamicTag$1.run(CustomTagLibrary.java:147)
at org.apache.commons.jelly.tags.define.InvokeBodyTag.doTag(InvokeBodyTag.java:91)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:262)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:186)
at org.apache.commons.jelly.impl.StaticTag.doTag(StaticTag.java:65)
at org.apache.commons.jelly.impl.StaticTagScript.run(StaticTagScript.java:112)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:186)
at org.apache.commons.jelly.impl.StaticTag.doTag(StaticTag.java:65)
at org.apache.commons.jelly.impl.StaticTagScript.run(StaticTagScript.java:112)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:186)
at org.apache.commons.jelly.impl.StaticTag.doTag(StaticTag.java:65)
at org.apache.commons.jelly.impl.StaticTagScript.run(StaticTagScript.java:112)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:186)
at org.apache.commons.jelly.impl.StaticTag.doTag(StaticTag.java:65)
at org.apache.commons.jelly.impl.StaticTagScript.run(StaticTagScript.java:112)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:186)
at org.apache.commons.jelly.impl.StaticTag.doTag(StaticTag.java:65)
at org.apache.commons.jelly.impl.StaticTagScript.run(StaticTagScript.java:112)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:186)
at org.apache.commons.jelly.impl.StaticTag.doTag(StaticTag.java:65)
at org.apache.commons.jelly.impl.StaticTagScript.run(StaticTagScript.java:112)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:186)
at org.apache.commons.jelly.tags.core.JellyTag.doTag(JellyTag.java:45)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:262)
at org.apache.commons.jelly.impl.DynamicTag.doTag(DynamicTag.java:81)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:262)
at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:186)
at org.apache.commons.jelly.tags.core.JellyTag.doTag(JellyTag.java:45)
at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:262)
at org.kohsuke.stapler.jelly.DefaultScriptInvoker.invokeScript(DefaultScriptInvoker.java:29)
at org.kohsuke.stapler.jelly.JellyClassTearOff.serveIndexJelly(JellyClassTearOff.java:43)
at org.kohsuke.stapler.jelly.JellyFacet.handleIndexRequest(JellyFacet.java:83)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:481)
at org.kohsuke.stapler.MetaClass$6.doDispatch(MetaClass.java:180)
at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:492)
at org.kohsuke.stapler.MetaClass$6.doDispatch(MetaClass.java:180)
at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:492)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:408)
at org.kohsuke.stapler.Stapler.service(Stapler.java:117)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:45)
at winstone.ServletConfiguration.execute(ServletConfiguration.java:249)
at winstone.RequestDispatcher.forward(RequestDispatcher.java:335)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:378)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:94)
at org.jvnet.hudson.plugins.greenballs.GreenBallFilter.doFilter(GreenBallFilter.java:47)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:97)
at hudson.plugins.audit_trail.AuditTrailFilter.doFilter(AuditTrailFilter.java:64)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:97)
at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:86)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:195)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:368)
at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:47)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:195)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:368)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84)
at hudson.security.UnwrapSecurityExceptionFilter.doFilter(UnwrapSecurityExceptionFilter.java:51)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:166)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.providers.anonymous.AnonymousProcessingFilter.doFilter(AnonymousProcessingFilter.java:125)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.rememberme.RememberMeProcessingFilter.doFilter(RememberMeProcessingFilter.java:142)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.AbstractProcessingFilter.doFilter(AbstractProcessingFilter.java:271)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.basicauth.BasicProcessingFilter.doFilter(BasicProcessingFilter.java:173)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:249)
at hudson.security.HttpSessionContextIntegrationFilter2.doFilter(HttpSessionContextIntegrationFilter2.java:66)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:76)
at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:164)
at winstone.FilterConfiguration.execute(FilterConfiguration.java:195)
at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:368)
at winstone.RequestDispatcher.forward(RequestDispatcher.java:333)
at winstone.RequestHandlerThread.processRequest(RequestHandlerThread.java:244)
at winstone.RequestHandlerThread.run(RequestHandlerThread.java:150)
at java.lang.Thread.run(Thread.java:810)
Caused by: java.lang.ClassNotFoundException: hudson.model.Job
at java.lang.Class.forNameImpl(Native Method)
at java.lang.Class.forName(Class.java:130)
at sun.reflect.GeneratedMethodAccessor1117.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:618)
at org.apache.commons.jelly.tags.core.InvokeStaticTag.doTag(InvokeStaticTag.java:125)
... 125 more

A restart of the system makes it disappear for a time, but it eventually reoccurs.