JSF2 NullPointerException instead of ViewExpiredException

Question

I use Mojarra 2.2.2, PrimeFaces 4.0, OmniFaces 1.7, Tomcat 7, Weld.

Following stacktrace appears when session expires on server and ajax request is sent:

java.lang.NullPointerException
at com.sun.faces.context.PartialViewContextImpl.createPartialResponseWriter(PartialViewContextImpl.java:485)
at com.sun.faces.context.PartialViewContextImpl.access$300(PartialViewContextImpl.java:73)
at com.sun.faces.context.PartialViewContextImpl$DelayedInitPartialResponseWriter.getWrapped(PartialViewContextImpl.java:619)
at javax.faces.context.PartialResponseWriter.startDocument(PartialResponseWriter.java:116)
at org.omnifaces.context.OmniPartialViewContext$OmniPartialResponseWriter.startDocument(OmniPartialViewContext.java:270)
at org.primefaces.context.PrimePartialResponseWriter.startDocument(PrimePartialResponseWriter.java:134)
at com.sun.faces.context.AjaxExceptionHandlerImpl.handlePartialResponseError(AjaxExceptionHandlerImpl.java:201)
at com.sun.faces.context.AjaxExceptionHandlerImpl.handle(AjaxExceptionHandlerImpl.java:126)
at javax.faces.context.ExceptionHandlerWrapper.handle(ExceptionHandlerWrapper.java:100)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:119)
at com.sun.faces.lifecycle.RestoreViewPhase.doPhase(RestoreViewPhase.java:121)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:646)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.meb.lotrlcg.web.core.TrackSessionFilter.doFilter(TrackSessionFilter.java:80)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
at java.lang.Thread.run(Thread.java:662)

Why NullPointerException is thrown instead ViewExpiredException? How can I handle this the right way? I registered an exception handler in faces-config.xml and added an appriopriate error page in web-xml.

Answer 1

Solved (kind of...) - it seems that enabling partial state saving (which is the default behavior) in web.xml did the trick and ViewExpiredException is thrown as expected.

<context-param>
    <param-name>javax.faces.PARTIAL_STATE_SAVING</param-name>
    <param-value>true</param-value>
</context-param>

Still I don't know why it worked.

Answer 2

Just ran into this as well as was able to work around it with the same javax.faces.PARTIAL_STATE_SAVING=true on 2.2.12

Opening https://java.net/jira/browse/JAVASERVERFACES-4193