NullPointerException in DashboardPanel when collapsing widget

[jchappelle]

Every now and then I get an error when clicking the collapse link. Below is the stack trace. It looks like the transient DashboardContext is null. I had a chrome browser and an IE 11 browser up and it was happening with both at the same time.

java.lang.NullPointerException at ro.fortsoft.wicket.dashboard.web.DashboardPanel.onWidgetsSorted(DashboardPanel.java:100) at ro.fortsoft.wicket.dashboard.web.DashboardPanel.onEvent(DashboardPanel.java:76) at org.apache.wicket.settings.def.FrameworkSettings.dispatchEvent(FrameworkSettings.java:132) at org.apache.wicket.ComponentEventSender.dispatchToComponent(ComponentEventSender.java:282) at org.apache.wicket.ComponentEventSender.access$100(ComponentEventSender.java:36) at org.apache.wicket.ComponentEventSender$ComponentEventVisitor.component(ComponentEventSender.java:329) at org.apache.wicket.ComponentEventSender$ComponentEventVisitor.component(ComponentEventSender.java:306) at org.apache.wicket.util.visit.Visits.visitChildren(Visits.java:144) at org.apache.wicket.util.visit.Visits.visitChildren(Visits.java:162) at org.apache.wicket.util.visit.Visits.visitChildren(Visits.java:123) at org.apache.wicket.util.visit.Visits.visitChildren(Visits.java:192) at org.apache.wicket.MarkupContainer.visitChildren(MarkupContainer.java:875) at org.apache.wicket.ComponentEventSender.breadth(ComponentEventSender.java:160) at org.apache.wicket.ComponentEventSender.send(ComponentEventSender.java:68) at org.apache.wicket.Component.send(Component.java:4429) at ro.fortsoft.wicket.dashboard.web.DashboardColumnPanel$2.onSort(DashboardColumnPanel.java:109) at ro.fortsoft.wicket.dashboard.web.SortableAjaxBehavior.respond(SortableAjaxBehavior.java:59) at org.apache.wicket.ajax.AbstractDefaultAjaxBehavior.onRequest(AbstractDefaultAjaxBehavior.java:633) at java.lang.reflect.Method.invoke(Method.java:606) at org.apache.wicket.RequestListenerInterface.internalInvoke(RequestListenerInterface.java:258) at org.apache.wicket.RequestListenerInterface.invoke(RequestListenerInterface.java:241) at org.apache.wicket.core.request.handler.ListenerInterfaceRequestHandler.invokeListener(ListenerInterfaceRequestHandler.java:250) at org.apache.wicket.core.request.handler.ListenerInterfaceRequestHandler.respond(ListenerInterfaceRequestHandler.java:236) at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:862) 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.WicketFilter.doFilter(WicketFilter.java:282) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1291) at org.springframework.orm.hibernate4.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:152) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1291) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:443) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:556) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:227) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1044) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:372) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:189) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:978) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135) at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:255) at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:154) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116) at org.eclipse.jetty.server.Server.handle(Server.java:369) at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:486) at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:933) at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:995) at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:644) at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:235) at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82) at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:668) at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:52) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608) at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543) at java.lang.Thread.run(Thread.java:744)

Complete stack:

org.apache.wicket.WicketRuntimeException: Method onRequest of interface org.apache.wicket.behavior.IBehaviorListener targeted at ro.fortsoft.wicket.dashboard.web.DashboardColumnPanel$2@16a626b2 on component [WebMarkupContainer [Component id = columnContainer]] threw an exception at org.apache.wicket.RequestListenerInterface.internalInvoke(RequestListenerInterface.java:268) at org.apache.wicket.RequestListenerInterface.invoke(RequestListenerInterface.java:241) at org.apache.wicket.core.request.handler.ListenerInterfaceRequestHandler.invokeListener(ListenerInterfaceRequestHandler.java:250) at org.apache.wicket.core.request.handler.ListenerInterfaceRequestHandler.respond(ListenerInterfaceRequestHandler.java:236) at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:862) 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)

java.lang.reflect.InvocationTargetException at sun.reflect.GeneratedMethodAccessor177.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.apache.wicket.RequestListenerInterface.internalInvoke(RequestListenerInterface.java:258) 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:862) 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)

[jchappelle]

This seems to only happen when I try to sort after clicking the DetachAction. I'm able to make it happen in the demo sometimes but in my custom application all the time.