This is my TreeTable definition on xhtml page:

```
<p:treeTable var="r" value="#{mybean.tree}">

```

I can see in catalina.out file that every day this happens a few times:

```
12-Jan-2015 10:13:00.119 SEVERE [ajp-apr-8009-exec-211] com.sun.faces.application.view.FaceletViewHandlingStrategy.handleRenderException Error Rendering View[/my_page.xhtml]
     java.lang.NullPointerException
        at org.primefaces.component.treetable.TreeTableRenderer.encodeEnd(TreeTableRenderer.java:127)
        at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:919)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1863)
        at com.sun.faces.context.PartialViewContextImpl$PhaseAwareVisitCallback.visit(PartialViewContextImpl.java:582)
        at com.sun.faces.component.visit.PartialVisitContext.invokeVisitCallback(PartialVisitContext.java:183)
        at org.primefaces.component.api.UITree.visitTree(UITree.java:648)
        at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
        at javax.faces.component.UIForm.visitTree(UIForm.java:371)
        at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
        at com.sun.faces.context.PartialViewContextImpl.processComponents(PartialViewContextImpl.java:403)
        at com.sun.faces.context.PartialViewContextImpl.processPartial(PartialViewContextImpl.java:322)
        at org.primefaces.context.PrimePartialViewContext.processPartial(PrimePartialViewContext.java:60)
        at javax.faces.component.UIViewRoot.encodeChildren(UIViewRoot.java:1004)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1856)
        at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:430)
        at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:133)
        at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120)
        at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
        at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219)
        at javax.faces.webapp.FacesServlet.service(FacesServlet.java:647)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
        at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)
        at org.apache.coyote.ajp.AbstractAjpProcessor.process(AbstractAjpProcessor.java:831)
        at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
        at org.apache.tomcat.util.net.AprEndpoint$SocketWithOptionsProcessor.run(AprEndpoint.java:2344)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$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)

    12-Jan-2015 10:13:00.120 SEVERE [ajp-apr-8009-exec-211] com.sun.faces.context.AjaxExceptionHandlerImpl.handlePartialResponseError java.lang.NullPointerException
        at org.primefaces.component.treetable.TreeTableRenderer.encodeEnd(TreeTableRenderer.java:127)
        at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:919)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1863)
        at com.sun.faces.context.PartialViewContextImpl$PhaseAwareVisitCallback.visit(PartialViewContextImpl.java:582)
        at com.sun.faces.component.visit.PartialVisitContext.invokeVisitCallback(PartialVisitContext.java:183)
        at org.primefaces.component.api.UITree.visitTree(UITree.java:648)
        at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
        at javax.faces.component.UIForm.visitTree(UIForm.java:371)
        at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
        at com.sun.faces.context.PartialViewContextImpl.processComponents(PartialViewContextImpl.java:403)
        at com.sun.faces.context.PartialViewContextImpl.processPartial(PartialViewContextImpl.java:322)
        at org.primefaces.context.PrimePartialViewContext.processPartial(PrimePartialViewContext.java:60)
        at javax.faces.component.UIViewRoot.encodeChildren(UIViewRoot.java:1004)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1856)
        at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:430)
        at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:133)
        at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120)
        at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
        at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219)
        at javax.faces.webapp.FacesServlet.service(FacesServlet.java:647)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
        at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)
        at org.apache.coyote.ajp.AbstractAjpProcessor.process(AbstractAjpProcessor.java:831)
        at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
        at org.apache.tomcat.util.net.AprEndpoint$SocketWithOptionsProcessor.run(AprEndpoint.java:2344)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$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)

```

I haven't gottten any user complaints and am not sure yet what the user is doing when this happens. I was assuming she is just opening the page but because of `handlePartialResponseError` I guess it could be also expanding/collapsing.

Does the error indicate that my object is `null` in one entry of the tree? In my code I have made sure no nulls are added so this should not be the case.

`mybean` is a `@SessionScoped` `@ManagedBean` (used to be `@ViewScoped` but now the tree is cached for each user).

My setup is:

* Tomcat 8.0.15
* Mojarra 2.2.8
* Primefaces 5.1
* RHEL 7.0