javax.servlet.ServletException: java.lang.NullPointerException
	at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:778)
	at org.kohsuke.stapler.Stapler.invoke(Stapler.java:858)
	at org.kohsuke.stapler.MetaClass$6.doDispatch(MetaClass.java:248)
	at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:53)
	at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:728)
	at org.kohsuke.stapler.Stapler.invoke(Stapler.java:858)
	at org.kohsuke.stapler.Stapler.invoke(Stapler.java:631)
	at org.kohsuke.stapler.Stapler.service(Stapler.java:225)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
	at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:491)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1074)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:96)
	at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:88)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1065)
	at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:48)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1065)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84)
	at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:76)
	at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:164)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1065)
	at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:46)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1065)
	at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:81)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1065)
	at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:365)
	at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:185)
	at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
	at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:689)
	at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:391)
	at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:146)
	at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
	at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:139)
	at org.mortbay.jetty.Server.handle(Server.java:285)
	at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:457)
	at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:765)
	at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:628)
	at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:209)
	at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:357)
	at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:329)
	at org.mortbay.thread.BoundedThreadPool$PoolThread.run(BoundedThreadPool.java:475)
Caused by: java.lang.NullPointerException
	at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:187)
	at com.google.common.collect.SingletonImmutableSet.<init>(SingletonImmutableSet.java:47)
	at com.google.common.collect.ImmutableSet.of(ImmutableSet.java:88)
	at com.google.common.collect.ImmutableSet.copyFromCollection(ImmutableSet.java:341)
	at com.google.common.collect.ImmutableSet.copyOf(ImmutableSet.java:329)
	at com.google.common.collect.Sets$CartesianSet$Axis.<init>(Sets.java:1086)
	at com.google.common.collect.Sets$CartesianSet.<init>(Sets.java:998)
	at com.google.common.collect.Sets.cartesianProduct(Sets.java:935)
	at hudson.matrix.AxisList.list(AxisList.java:82)
	at hudson.matrix.MatrixProject.rebuildConfigurations(MatrixProject.java:630)
	at hudson.matrix.MatrixProject.submit(MatrixProject.java:887)
	at hudson.model.Job.doConfigSubmit(Job.java:1154)
	at hudson.model.AbstractProject.doConfigSubmit(AbstractProject.java:773)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:298)
	at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:161)
	at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:96)
	at org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:120)
	at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:53)
	at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:728)
	... 39 more