I just got a 503 when opening the splash 2018 homepage with the trace below. A refresh loaded the page just normally. I see more instances pop up every x hours in the error log. I suspect some comparison function not being thread safe:

[12 Oct 14:54:15 conference] WARN  com.google.common.util.concurrent.UncheckedExecutionException: java.lang.IllegalArgumentException: Comparison method violates its general contract!
[12 Oct 14:54:15 conference] ERROR Exception in dispatch servlet: java.lang.IllegalArgumentException: Comparison method violates its general contract!
[12 Oct 14:54:15 conference] ERROR EXCEPTION
com.google.common.util.concurrent.UncheckedExecutionException: java.lang.IllegalArgumentException: Comparison method violates its general contract!
	at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2203)
	at com.google.common.cache.LocalCache.get(LocalCache.java:3937)
	at com.google.common.cache.LocalCache$LocalManualCache.get(LocalCache.java:4739)
	at utils.AbstractPageServlet.renderOrInitAction(AbstractPageServlet.java:395)
	at utils.AbstractPageServlet.serve(AbstractPageServlet.java:186)
	at utils.DispatchServletHelper.handlePage(DispatchServletHelper.java:1084)
	at utils.DispatchServletHelper.doServe(DispatchServletHelper.java:1029)
	at utils.DispatchServlet.doGet(DispatchServlet.java:486)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:108)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:522)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:1102)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:788)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1485)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalArgumentException: Comparison method violates its general contract!
	at java.util.TimSort.mergeHi(TimSort.java:899)
	at java.util.TimSort.mergeAt(TimSort.java:516)
	at java.util.TimSort.mergeForceCollapse(TimSort.java:457)
	at java.util.TimSort.sort(TimSort.java:254)
	at java.util.Arrays.sort(Arrays.java:1512)
	at java.util.ArrayList.sort(ArrayList.java:1454)
	at java.util.Collections.sort(Collections.java:175)
	at webdsl.generated.functions.ent_EventsElem_listCompr0List_Event__.ent_EventsElem_listCompr0List_Event__(ent_EventsElem_listCompr0List_Event__.java:13)
	at webdsl.generated.domain.EventsElem.getEvents_(EventsElem.java:234)
	at webdsl.generated.templates.outputEventsElem_Template.handlePhase(outputEventsElem_Template.java:135)
	at utils.TemplateServlet.renderInternal(TemplateServlet.java:140)
	at utils.TemplateServlet.render(TemplateServlet.java:119)
	at utils.TemplateServlet.handleTemplateCall(TemplateServlet.java:303)
	at webdsl.generated.templates.outputPageElem_Template.handlePhase(outputPageElem_Template.java:142)
	at utils.TemplateServlet.renderInternal(TemplateServlet.java:140)
	at utils.TemplateServlet.render(TemplateServlet.java:119)
	at utils.TemplateServlet.handleTemplateCall(TemplateServlet.java:303)
	at webdsl.generated.templates.showInCustomOrderList_PageElem__Template.handlePhase(showInCustomOrderList_PageElem__Template.java:141)
	at utils.TemplateServlet.renderInternal(TemplateServlet.java:140)
	at utils.TemplateServlet.render(TemplateServlet.java:119)
	at utils.TemplateServlet.handleTemplateCall(TemplateServlet.java:303)
	at webdsl.generated.templates.showPrimaryContentHomepage_Template.handlePhase(showPrimaryContentHomepage_Template.java:93)
	at utils.TemplateServlet.renderInternal(TemplateServlet.java:140)
	at utils.TemplateServlet.render(TemplateServlet.java:119)
	at utils.TemplateServlet.handleTemplateCall(TemplateServlet.java:303)
	at webdsl.generated.templates.conferenceHomeContentHomepage_Template.handlePhase(conferenceHomeContentHomepage_Template.java:187)
	at utils.TemplateServlet.renderInternal(TemplateServlet.java:140)
	at utils.TemplateServlet.render(TemplateServlet.java:119)
	at utils.TemplateServlet.handleTemplateCall(TemplateServlet.java:303)
	at webdsl.generated.templates.conferenceHomePageConferenceEdition_ta7ConferenceEdition_List_ImportantDate__ConferenceEdition_String_List_Track__Int_Homepage_Bool_Template.handlePhase(conferenceHomePageConferenceEdition_ta7ConferenceEdition_List_ImportantDate__ConferenceEdition_String_List_Track__Int_Homepage_Bool_Template.java:200)
	at utils.TemplateServlet.renderInternal(TemplateServlet.java:140)
	at utils.TemplateServlet.render(TemplateServlet.java:119)
	at utils.TemplateServlet.handleTemplateCall(TemplateServlet.java:303)
	at webdsl.generated.templates.containerBody_ta0_Template.handlePhase(containerBody_ta0_Template.java:73)
	at utils.TemplateServlet.renderInternal(TemplateServlet.java:140)
	at utils.TemplateServlet.render(TemplateServlet.java:119)
	at utils.TemplateServlet.handleTemplateCall(TemplateServlet.java:303)
	at webdsl.generated.templates.gridContainer_ta0_Template.handlePhase(gridContainer_ta0_Template.java:73)
	at utils.TemplateServlet.renderInternal(TemplateServlet.java:140)
	at utils.TemplateServlet.render(TemplateServlet.java:119)
	at utils.TemplateServlet.handleTemplateCall(TemplateServlet.java:303)
	at webdsl.generated.templates.div_Template.handlePhase(div_Template.java:77)
	at utils.TemplateServlet.renderInternal(TemplateServlet.java:140)
	at utils.TemplateServlet.render(TemplateServlet.java:119)
	at utils.TemplateServlet.handleTemplateCall(TemplateServlet.java:303)
	at webdsl.generated.templates.gridContainer_Template.handlePhase(gridContainer_Template.java:80)
	at utils.TemplateServlet.renderInternal(TemplateServlet.java:140)
	at utils.TemplateServlet.render(TemplateServlet.java:119)
	at utils.TemplateServlet.handleTemplateCall(TemplateServlet.java:303)
	at webdsl.generated.templates.containerBody_Template.handlePhase(containerBody_Template.java:79)
	at utils.TemplateServlet.renderInternal(TemplateServlet.java:140)
	at utils.TemplateServlet.render(TemplateServlet.java:119)
	at utils.TemplateServlet.handleTemplateCall(TemplateServlet.java:303)
	at webdsl.generated.templates.conferenceHomePageConferenceEdition_ta8ConferenceEdition_List_ImportantDate__ConferenceEdition_String_List_Track__Int_Homepage_Bool_Template.handlePhase(conferenceHomePageConferenceEdition_ta8ConferenceEdition_List_ImportantDate__ConferenceEdition_String_List_Track__Int_Homepage_Bool_Template.java:159)
	at utils.TemplateServlet.renderInternal(TemplateServlet.java:140)
	at utils.TemplateServlet.render(TemplateServlet.java:119)
	at utils.TemplateServlet.handleTemplateCall(TemplateServlet.java:303)
	at webdsl.generated.templates.bmainNoContainerConferenceEdition_String_Template.handlePhase(bmainNoContainerConferenceEdition_String_Template.java:209)
	at utils.TemplateServlet.renderInternal(TemplateServlet.java:140)
	at utils.TemplateServlet.render(TemplateServlet.java:119)
	at utils.TemplateServlet.handleTemplateCall(TemplateServlet.java:303)
	at webdsl.generated.templates.conferenceHomePageConferenceEdition_Template.handlePhase(conferenceHomePageConferenceEdition_Template.java:158)
	at utils.TemplateServlet.renderInternal(TemplateServlet.java:140)
	at utils.TemplateServlet.render(TemplateServlet.java:119)
	at utils.TemplateServlet.handleTemplateCall(TemplateServlet.java:303)
	at webdsl.generated.templates.home_Template.handlePhase(home_Template.java:125)
	at utils.TemplateServlet.renderInternal(TemplateServlet.java:140)
	at utils.TemplateServlet.render(TemplateServlet.java:119)
	at utils.AbstractPageServlet.renderPageOrTemplateContents(AbstractPageServlet.java:449)
	at utils.AbstractPageServlet$1.call(AbstractPageServlet.java:400)
	at utils.AbstractPageServlet$1.call(AbstractPageServlet.java:396)
	at com.google.common.cache.LocalCache$LocalManualCache$1.load(LocalCache.java:4742)
	at com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3527)
	at com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2319)
	at com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2282)
	at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2197)
	... 30 more

Submitted by Elmer van Chastelet on 12 October 2018 at 14:58