FreeMarker template error (DEBUG mode; use RETHROW in production!): The following has evaluated to null or missing: ==> spring [in template "open/vlab/exercises.ftl" at line 9, column 14] ---- Tip: If the failing expression is known to legally refer to something that's sometimes null or missing, either specify a default value like myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing</#if>. (These only cover the last step of the expression; to cover the whole expression, use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)?? ---- ---- FTL stack trace ("~" means nesting-related): - Failed at: @spring.message "exercises.title" [in template "open/vlab/exercises.ftl" at line 9, column 12] ---- Java stack trace (for programmers): ---- freemarker.core.InvalidReferenceException: [... Exception message was already printed; see it above ...] at freemarker.core.InvalidReferenceException.getInstance(InvalidReferenceException.java:134) at freemarker.core.UnexpectedTypeException.newDescriptionBuilder(UnexpectedTypeException.java:85) at freemarker.core.UnexpectedTypeException.<init>(UnexpectedTypeException.java:48) at freemarker.core.NonHashException.<init>(NonHashException.java:49) at freemarker.core.Dot._eval(Dot.java:48) at freemarker.core.Expression.eval(Expression.java:101) at freemarker.core.UnifiedCall.accept(UnifiedCall.java:74) at freemarker.core.Environment.visit(Environment.java:335) at freemarker.core.Environment.visit(Environment.java:341) at freemarker.core.Environment.process(Environment.java:314) at freemarker.template.Template.process(Template.java:383) at org.springframework.web.servlet.view.freemarker.FreeMarkerView.processTemplate(FreeMarkerView.java:391) at org.springframework.web.servlet.view.freemarker.FreeMarkerView.doRender(FreeMarkerView.java:304) at org.springframework.web.servlet.view.freemarker.FreeMarkerView.renderMergedTemplateModel(FreeMarkerView.java:255) at org.springframework.web.servlet.view.AbstractTemplateView.renderMergedOutputModel(AbstractTemplateView.java:181) at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:316) at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1406) at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1150) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1089) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:965) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) at javax.servlet.http.HttpServlet.service(HttpServlet.java:529) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) at javax.servlet.http.HttpServlet.service(HttpServlet.java:623) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:197) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:399) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at cn.net.rainier.global.filter.SqlInjectFilter.doFilter(SqlInjectFilter.java:80) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at org.springframework.web.servlet.resource.ResourceUrlEncodingFilter.doFilter(ResourceUrlEncodingFilter.java:67) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at cn.net.rainier.visit.filter.SetVisitLogFilter.doFilterInternal(SetVisitLogFilter.java:150) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at cn.net.rainier.user.security.filter.RefererCsrfFilter.doFilterInternal(RefererCsrfFilter.java:68) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at cn.net.rainier.user.security.filter.SetClientInfoFilter.doFilterInternal(SetClientInfoFilter.java:72) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at com.alibaba.druid.support.http.WebStatFilter.doFilter(WebStatFilter.java:124) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at cn.net.rainier.open.filter.IlabxAuthenticationTokenFilter.doFilterInternal(IlabxAuthenticationTokenFilter.java:850) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at cn.net.rainier.inbound.filter.InBoundFilter.doFilterInternal(InBoundFilter.java:38) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at cn.net.rainier.global.filter.CookieValidFilter.doFilterInternal(CookieValidFilter.java:40) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at org.jasig.cas.client.util.AssertionThreadLocalFilter.doFilter(AssertionThreadLocalFilter.java:51) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at org.ly.uap.client.util.TransNameFilter.doFilter(TransNameFilter.java:31) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at org.jasig.cas.client.util.HttpServletRequestWrapperFilter.doFilter(HttpServletRequestWrapperFilter.java:72) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at org.jasig.cas.client.session.SingleSignOutFilter.doFilter(SingleSignOutFilter.java:94) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at cn.net.rainier.core.xss.XssFilter.doFilter(XssFilter.java:42) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:337) at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:115) at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:81) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:122) at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:116) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:126) at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:81) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:109) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.authentication.rememberme.RememberMeAuthenticationFilter.doFilter(RememberMeAuthenticationFilter.java:141) at org.springframework.security.web.authentication.rememberme.RememberMeAuthenticationFilter.doFilter(RememberMeAuthenticationFilter.java:97) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:149) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilterInternal(BasicAuthenticationFilter.java:164) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:223) at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:217) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at cn.net.rainier.user.security.handler.RsaLoginFilter.doFilter(RsaLoginFilter.java:102) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at cn.net.rainier.user.security.handler.CaptchaValidFilter.doFilter(CaptchaValidFilter.java:56) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:103) at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:89) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.header.HeaderWriterFilter.doHeadersAfter(HeaderWriterFilter.java:90) at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:75) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:112) at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:82) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:55) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.session.DisableEncodeUrlFilter.doFilterInternal(DisableEncodeUrlFilter.java:42) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:346) at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:221) at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:186) at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:354) at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:267) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:94) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at org.springframework.session.web.http.SessionRepositoryFilter.doFilterInternal(SessionRepositoryFilter.java:142) at org.springframework.session.web.http.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:82) at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:354) at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:267) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:96) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:166) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:88) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:481) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:83) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:83) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:72) at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:763) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:344) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:398) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:935) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1831) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52) at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:973) at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:491) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:63) at java.lang.Thread.run(Thread.java:748)