NPE when listing users for attendance item

[mpellicer]

Seen this in production, only happens in specific items.

02-Jun-2021 13:26:29.810 WARN [http-nio-8080-exec-3659] org.sakaiproject.portal.charon.handlers.SiteHandler.doSite Redirecting tool inline url: https://XXXXXXX/portal/site/YYYYYYY/tool/5c1cf9d3-f5f3-4bca-8f41-8e4163890775 org.apache.wicket.WicketRuntimeException: Method onRequest of interface org.apache.wicket.behavior.IBehaviorListener targeted at org.apache.wicket.extensions.ajax.markup.html.AjaxLazyLoadPanel$1@5ae8e5e6 on component [AjaxLazyLoadPanel [Component id = dataPanelSlow]] threw an exception at org.apache.wicket.RequestListenerInterface.internalInvoke(RequestListenerInterface.java:268) at org.apache.wicket.RequestListenerInterface.invoke(RequestListenerInterface.java:241) at org.apache.wicket.core.request.handler.ListenerInterfaceRequestHandler.invokeListener(ListenerInterfaceRequestHandler.java:250) at org.apache.wicket.core.request.handler.ListenerInterfaceRequestHandler.respond(ListenerInterfaceRequestHandler.java:236) at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:890) at org.apache.wicket.request.RequestHandlerStack.execute(RequestHandlerStack.java:64) at org.apache.wicket.request.cycle.RequestCycle.execute(RequestCycle.java:261) at org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:218) at org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:289) at org.apache.wicket.protocol.http.WicketFilter.processRequestCycle(WicketFilter.java:259) at org.apache.wicket.protocol.http.WicketFilter.processRequest(WicketFilter.java:201) at org.apache.wicket.protocol.http.WicketServlet.doGet(WicketServlet.java:137) at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.sakaiproject.util.RequestFilter.doFilter(RequestFilter.java:426) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:712) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:459) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:352) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:312) at org.sakaiproject.tool.impl.ActiveToolComponent$MyActiveTool.forward(ActiveToolComponent.java:508) at org.sakaiproject.portal.charon.SkinnableCharonPortal.forwardTool(SkinnableCharonPortal.java:1496) at org.sakaiproject.portal.charon.handlers.SiteHandler.doSite(SiteHandler.java:478) at org.sakaiproject.portal.charon.handlers.SiteHandler.doGet(SiteHandler.java:275) at org.sakaiproject.portal.charon.handlers.SiteHandler.doGet(SiteHandler.java:163) at org.sakaiproject.portal.charon.SkinnableCharonPortal.doGet(SkinnableCharonPortal.java:853) at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.sakaiproject.util.RequestFilter.doFilter(RequestFilter.java:475) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:747) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1589) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Caused by: java.lang.reflect.InvocationTargetException at sun.reflect.GeneratedMethodAccessor2422.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.wicket.RequestListenerInterface.internalInvoke(RequestListenerInterface.java:258) ... 56 more Caused by: java.lang.NullPointerException 02-Jun-2021 13:26:30.753 ERROR [http-nio-8080-exec-3652] org.apache.wicket.DefaultExceptionMapper.mapUnexpectedExceptions Unexpected error occurred org.apache.wicket.WicketRuntimeException: Method onRequest of interface org.apache.wicket.behavior.IBehaviorListener targeted at org.apache.wicket.extensions.ajax.markup.html.AjaxLazyLoadPanel$1@5ae8e5e6 on component [AjaxLazyLoadPanel [Component id = dataPanelSlow]] threw an exception at org.apache.wicket.RequestListenerInterface.internalInvoke(RequestListenerInterface.java:268) at org.apache.wicket.RequestListenerInterface.invoke(RequestListenerInterface.java:241) at org.apache.wicket.core.request.handler.ListenerInterfaceRequestHandler.invokeListener(ListenerInterfaceRequestHandler.java:250) at org.apache.wicket.core.request.handler.ListenerInterfaceRequestHandler.respond(ListenerInterfaceRequestHandler.java:236) at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:890) at org.apache.wicket.request.RequestHandlerStack.execute(RequestHandlerStack.java:64) at org.apache.wicket.request.cycle.RequestCycle.execute(RequestCycle.java:261) at org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:218) at org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:289) at org.apache.wicket.protocol.http.WicketFilter.processRequestCycle(WicketFilter.java:259) at org.apache.wicket.protocol.http.WicketFilter.processRequest(WicketFilter.java:201) at org.apache.wicket.protocol.http.WicketServlet.doGet(WicketServlet.java:137) at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.sakaiproject.util.RequestFilter.doFilter(RequestFilter.java:426) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:712) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:459) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:352) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:312) at org.sakaiproject.tool.impl.ActiveToolComponent$MyActiveTool.forward(ActiveToolComponent.java:508) at org.sakaiproject.portal.charon.SkinnableCharonPortal.forwardTool(SkinnableCharonPortal.java:1496) at org.sakaiproject.portal.charon.handlers.SiteHandler.doSite(SiteHandler.java:478) at org.sakaiproject.portal.charon.handlers.SiteHandler.doGet(SiteHandler.java:275) at org.sakaiproject.portal.charon.handlers.SiteHandler.doGet(SiteHandler.java:163) at org.sakaiproject.portal.charon.SkinnableCharonPortal.doGet(SkinnableCharonPortal.java:853) at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.sakaiproject.util.RequestFilter.doFilter(RequestFilter.java:475) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:747) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1589) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Caused by: java.lang.reflect.InvocationTargetException at sun.reflect.GeneratedMethodAccessor2422.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.wicket.RequestListenerInterface.internalInvoke(RequestListenerInterface.java:258) ... 56 more Caused by: java.lang.NullPointerException

[mpellicer]

If helps, also fails when trying to export:

org.apache.wicket.WicketRuntimeException: Method onLinkClicked of interface org.apache.wicket.markup.html.link.ILinkListener targeted at [DownloadLink [Component id = submit-link]] on component [DownloadLink [Component id = submit-link]] threw an exception at org.apache.wicket.RequestListenerInterface.internalInvoke(RequestListenerInterface.java:268) at org.apache.wicket.RequestListenerInterface.invoke(RequestListenerInterface.java:216) at org.apache.wicket.core.request.handler.ListenerInterfaceRequestHandler.invokeListener(ListenerInterfaceRequestHandler.java:243) at org.apache.wicket.core.request.handler.ListenerInterfaceRequestHandler.respond(ListenerInterfaceRequestHandler.java:236) at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:890) at org.apache.wicket.request.RequestHandlerStack.execute(RequestHandlerStack.java:64) at org.apache.wicket.request.cycle.RequestCycle.execute(RequestCycle.java:261) at org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:218) at org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:289) at org.apache.wicket.protocol.http.WicketFilter.processRequestCycle(WicketFilter.java:259) at org.apache.wicket.protocol.http.WicketFilter.processRequest(WicketFilter.java:201) at org.apache.wicket.protocol.http.WicketServlet.doGet(WicketServlet.java:137) at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.sakaiproject.util.RequestFilter.doFilter(RequestFilter.java:426) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:712) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:459) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:352) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:312) at org.sakaiproject.tool.impl.ActiveToolComponent$MyActiveTool.forward(ActiveToolComponent.java:508) at org.sakaiproject.portal.charon.SkinnableCharonPortal.forwardTool(SkinnableCharonPortal.java:1496) at org.sakaiproject.portal.charon.handlers.SiteHandler.doToolBuffer(SiteHandler.java:1254) at org.sakaiproject.portal.charon.handlers.SiteHandler.bufferContent(SiteHandler.java:1088) at org.sakaiproject.portal.charon.handlers.SiteHandler.doSite(SiteHandler.java:499) at org.sakaiproject.portal.charon.handlers.SiteHandler.doGet(SiteHandler.java:275) at org.sakaiproject.portal.charon.handlers.SiteHandler.doGet(SiteHandler.java:163) at org.sakaiproject.portal.charon.SkinnableCharonPortal.doGet(SkinnableCharonPortal.java:853) at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.sakaiproject.util.RequestFilter.doFilter(RequestFilter.java:475) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:747) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1589) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Caused by: java.lang.reflect.InvocationTargetException at sun.reflect.GeneratedMethodAccessor14446.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.wicket.RequestListenerInterface.internalInvoke(RequestListenerInterface.java:258) ... 58 more Caused by: java.lang.RuntimeException: An error occurred while getting the model object for Component: [DownloadLink [Component id = submit-link, page = org.sakaiproject.attendance.tool.pages.ExportPage, path = 2:export-form:submit-link.DownloadLink, isVisible = true, isVersioned = true]] at org.apache.wicket.Component.getDefaultModelObject(Component.java:1617) at org.apache.wicket.markup.html.link.Link.getModelObject(Link.java:438) at org.apache.wicket.markup.html.link.DownloadLink.onClick(DownloadLink.java:155) at org.apache.wicket.markup.html.link.Link.onLinkClicked(Link.java:190) ... 62 more Caused by: java.lang.NullPointerException at org.sakaiproject.attendance.tool.pages.ExportPage.buildExcelFile(ExportPage.java:210) at org.sakaiproject.attendance.tool.pages.ExportPage.access$000(ExportPage.java:58) at org.sakaiproject.attendance.tool.pages.ExportPage$3.load(ExportPage.java:105) at org.sakaiproject.attendance.tool.pages.ExportPage$3.load(ExportPage.java:101) at org.apache.wicket.model.LoadableDetachableModel.getObject(LoadableDetachableModel.java:124) at org.apache.wicket.Component.getDefaultModelObject(Component.java:1612) ... 65 more 02-Jun-2021 13:38:10.090 ERROR [http-nio-8080-exec-3644] org.apache.wicket.DefaultExceptionMapper.mapUnexpectedExceptions Unexpected error occurred org.apache.wicket.WicketRuntimeException: Method onLinkClicked of interface org.apache.wicket.markup.html.link.ILinkListener targeted at [DownloadLink [Component id = submit-link]] on component [DownloadLink [Component id = submit-link]] threw an exception at org.apache.wicket.RequestListenerInterface.internalInvoke(RequestListenerInterface.java:268) at org.apache.wicket.RequestListenerInterface.invoke(RequestListenerInterface.java:216) at org.apache.wicket.core.request.handler.ListenerInterfaceRequestHandler.invokeListener(ListenerInterfaceRequestHandler.java:243) at org.apache.wicket.core.request.handler.ListenerInterfaceRequestHandler.respond(ListenerInterfaceRequestHandler.java:236) at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:890) at org.apache.wicket.request.RequestHandlerStack.execute(RequestHandlerStack.java:64) at org.apache.wicket.request.cycle.RequestCycle.execute(RequestCycle.java:261) at org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:218) at org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:289) at org.apache.wicket.protocol.http.WicketFilter.processRequestCycle(WicketFilter.java:259) at org.apache.wicket.protocol.http.WicketFilter.processRequest(WicketFilter.java:201) at org.apache.wicket.protocol.http.WicketServlet.doGet(WicketServlet.java:137) at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.sakaiproject.util.RequestFilter.doFilter(RequestFilter.java:426) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:712) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:459) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:352) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:312) at org.sakaiproject.tool.impl.ActiveToolComponent$MyActiveTool.forward(ActiveToolComponent.java:508) at org.sakaiproject.portal.charon.SkinnableCharonPortal.forwardTool(SkinnableCharonPortal.java:1496) at org.sakaiproject.portal.charon.handlers.SiteHandler.doToolBuffer(SiteHandler.java:1254) at org.sakaiproject.portal.charon.handlers.SiteHandler.bufferContent(SiteHandler.java:1088) at org.sakaiproject.portal.charon.handlers.SiteHandler.doSite(SiteHandler.java:499) at org.sakaiproject.portal.charon.handlers.SiteHandler.doGet(SiteHandler.java:275) at org.sakaiproject.portal.charon.handlers.SiteHandler.doGet(SiteHandler.java:163) at org.sakaiproject.portal.charon.SkinnableCharonPortal.doGet(SkinnableCharonPortal.java:853) at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.sakaiproject.util.RequestFilter.doFilter(RequestFilter.java:475) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:747) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1589) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Caused by: java.lang.reflect.InvocationTargetException at sun.reflect.GeneratedMethodAccessor14446.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.wicket.RequestListenerInterface.internalInvoke(RequestListenerInterface.java:258) ... 58 more Caused by: java.lang.RuntimeException: An error occurred while getting the model object for Component: [DownloadLink [Component id = submit-link, page = org.sakaiproject.attendance.tool.pages.ExportPage, path = 2:export-form:submit-link.DownloadLink, isVisible = true, isVersioned = true]] at org.apache.wicket.Component.getDefaultModelObject(Component.java:1617) at org.apache.wicket.markup.html.link.Link.getModelObject(Link.java:438) at org.apache.wicket.markup.html.link.DownloadLink.onClick(DownloadLink.java:155) at org.apache.wicket.markup.html.link.Link.onLinkClicked(Link.java:190) ... 62 more Caused by: java.lang.NullPointerException at org.sakaiproject.attendance.tool.pages.ExportPage.buildExcelFile(ExportPage.java:210) at org.sakaiproject.attendance.tool.pages.ExportPage.access$000(ExportPage.java:58) at org.sakaiproject.attendance.tool.pages.ExportPage$3.load(ExportPage.java:105) at org.sakaiproject.attendance.tool.pages.ExportPage$3.load(ExportPage.java:101) at org.apache.wicket.model.LoadableDetachableModel.getObject(LoadableDetachableModel.java:124) at org.apache.wicket.Component.getDefaultModelObject(Component.java:1612) ... 65 more