I get an Error 500 from Tomcat about 30% of the time when I am submitting
changes to either a Hudson job configuration or the Hudson admin settings
(Manage Hudson->Configure System). It's just luck of the draw that the next
time I refresh the configuration page I will get the complete form.

Based on these forum threads, it seems there is intermitent missing content in
the page. I contend that this bug is not fixed by switching from localhost to
an IP addr or another URL. I have seen this behavior under both conditions.

Related threads:
http://www.nabble.com/ServletException:-This-page-expects-a-form-submission-td20521641.html
http://www.nabble.com/Server-Error:-400-td20103452.html

Environment:

• Hudson running on Tomcat6 on Ubuntu8.10 server (though I've seen it when
  running on my Ubuntu8.04 notebook as well under Jetty)
• Firefox3.0.4
• Hudson 1.263-SNAPSHOT, though I've seen it past releases

Here is the root cause Exception:

java.lang.Error: This page expects a form submission
org.kohsuke.stapler.RequestImpl.getSubmittedForm(RequestImpl.java:614)
hudson.model.Hudson.doConfigExecutorsSubmit(Hudson.java:1713)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:146)
org.kohsuke.stapler.Function.bindAndinvoke(Function.java:71)
org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:75)
org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:409)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:352)
org.kohsuke.stapler.Stapler.service(Stapler.java:112)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:61)
hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:53)
hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:52)
hudson.security.UnwrapSecurityExceptionFilter.doFilter(UnwrapSecurityExceptionFilter.java:28)
hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:55)
org.acegisecurity.ui.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:166)
hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:55)
org.acegisecurity.providers.anonymous.AnonymousProcessingFilter.doFilter(AnonymousProcessingFilter.java:125)
hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:55)
org.acegisecurity.ui.rememberme.RememberMeProcessingFilter.doFilter(RememberMeProcessingFilter.java:142)
hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:55)
org.acegisecurity.ui.AbstractProcessingFilter.doFilter(AbstractProcessingFilter.java:271)
hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:55)
org.acegisecurity.ui.basicauth.BasicProcessingFilter.doFilter(BasicProcessingFilter.java:173)
hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:55)
org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:249)
hudson.security.HttpSessionContextIntegrationFilter2.doFilter(HttpSessionContextIntegrationFilter2.java:42)
hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:55)
hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:44)
hudson.security.HudsonFilter.doFilter(HudsonFilter.java:85)