NullPointerException at a4j:include
Hi, I'm sorry for repeatedly posting about a4j:include, but I keep running into these problems that nobody seems to have seen before.
I ran into NPE while clicking on an a4j:commandButton inside the included page (using a4j:include). Here's the stack trace -
SEVERE: Servlet.service() for servlet jsp threw exception java.lang.NullPointerException at javax.faces.component.UIComponentBase$ChildrenList.remove(UIComponentBase.java:1567) at javax.faces.webapp.UIComponentTag.removeOldChildren(UIComponentTag.java:1205) at javax.faces.webapp.UIComponentTag.doEndTag(UIComponentTag.java:557) at org.ajax4jsf.taglib.html.jsp.IncludeTag.doEndTag(IncludeTag.java:176) at org.apache.jsp.reports.TestMain_jsp._jspx_meth_a4j_include_0(TestMain_jsp.java:190) at org.apache.jsp.reports.TestMain_jsp._jspx_meth_h_panelGroup_0(TestMain_jsp.java:166) at org.apache.jsp.reports.TestMain_jsp._jspx_meth_h_form_0(TestMain_jsp.java:139) at org.apache.jsp.reports.TestMain_jsp._jspx_meth_f_view_0(TestMain_jsp.java:106) at org.apache.jsp.reports.TestMain_jsp._jspService(TestMain_jsp.java:70) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97) at javax.servlet.http.HttpServlet.service(HttpServlet.java:802) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:334) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264) at javax.servlet.http.HttpServlet.service(HttpServlet.java:802) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173) at com.bluejungle.destiny.webui.framework.loginmgr.LoginFilterImpl.doFilter(LoginFilterImpl.java:125) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:672) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:463) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:398) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:301) at com.sun.faces.context.ExternalContextImpl.dispatch(ExternalContextImpl.java:346) at com.sun.faces.application.ViewHandlerImpl.renderView(ViewHandlerImpl.java:152) at com.bluejungle.destiny.webui.framework.faces.RequestParameterAllowingViewHandler.renderView(RequestParameterAllowingViewHandler.java:104) at com.bluejungle.destiny.webui.framework.faces.PrerenderActionViewHandler.renderView(PrerenderActionViewHandler.java:152) at com.bluejungle.destiny.webui.framework.faces.CompoundCustomViewHandler.renderView(CompoundCustomViewHandler.java:81) at org.ajax4jsf.framework.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:108) at org.ajax4jsf.framework.ajax.AjaxViewHandler.renderView(AjaxViewHandler.java:233) at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:107) at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:245) at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:137) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:214) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173) at org.ajax4jsf.framework.ajax.xmlfilter.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:127) at org.ajax4jsf.framework.ajax.xmlfilter.BaseFilter.doFilter(BaseFilter.java:277) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173) at com.bluejungle.destiny.webui.framework.loginmgr.LoginFilterImpl.doFilter(LoginFilterImpl.java:125) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869) at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664) at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527) at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684) at java.lang.Thread.run(Thread.java:595)
The command button click generates two FacesServlet requests, the first one is the actual command button request, and the second one is a request for the targeted include page to re-render. However it seems that in the Render View phase of the second request, while the doEndTag() method is called for the IncludeTag, something called removeOldChildren() will be called, which will attemp to remove all of the children of the old include page, but by this point, the child are all gone already, hence a NPE is thrown.
I stepped through the code everywhere and I'm really confused as to why this is happening. If anybody has seen this, any help would be greatly appreciated.
Robert
