java.lang.NullPointerException at com.sun.faces.context.flash.ELFlash.loggingGetPhaseMapForWriting

[durgakalyan yarragunta]

hi,
I am facing this below issue in JSF 2.0 + Spring + Hibernate + Apache Tomcat 7.x environment. can you anybody help me to fix it.
java.lang.NullPointerException
at com.sun.faces.context.flash.ELFlash.loggingGetPhaseMapForWriting(ELFlash.java:749)
at com.sun.faces.context.flash.ELFlash.getPhaseMapForWriting(ELFlash.java:783)
at com.sun.faces.context.flash.ELFlash.isEmpty(ELFlash.java:482)
at com.sun.faces.facelets.util.DevTools.writeVariables(DevTools.java:322)
at com.sun.faces.facelets.util.DevTools.writeVariables(DevTools.java:212)
at com.sun.faces.facelets.util.DevTools.debugHtml(DevTools.java:127)
at com.sun.faces.renderkit.RenderKitUtils.renderHtmlErrorPage(RenderKitUtils.java:1139)
at com.sun.faces.context.ExceptionHandlerImpl.throwIt(ExceptionHandlerImpl.java:249)
at com.sun.faces.context.ExceptionHandlerImpl.handle(ExceptionHandlerImpl.java:136)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:115)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:135)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:335)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:684)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:471)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:402)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:329)
at com.sun.faces.context.ExternalContextImpl.dispatch(ExternalContextImpl.java:542)
at com.sun.faces.application.view.JspViewHandlingStrategy.executePageToBuildView(JspViewHandlingStrategy.java:359)
at com.sun.faces.application.view.JspViewHandlingStrategy.buildView(JspViewHandlingStrategy.java:150)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:96)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:135)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:335)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:394)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:166)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)

[Tim Holloway]

Welcome to the JavaRanch, Durgakalyan!

Errors like this are actually often the results of an error in a backing bean and unfortunately, there's rarely good context to aid you in tracking down the cause of the fault.

What I generally end up doing is run the project in Eclipse with breakpoint on NullPointerException and walk my way up the stack, looking at the stackframes in the hopes that one of them will contain the actual EL expression that was being processed, then breakpoint the set/get methods of the variables, rerun the request and walk into the set/get methods. Not exactly child's play, but its what they pay me the big bucks for (or little pennies, these days).

One problem is that a lot of other things throw and consume NPE's besides actual bugs, so to minimize the number of false breakpoints, you want to keep the breakpoint switched off as long as you can. It's helpful if you can breakpoint the actual failing code line rather than all cases of NPE, but that's harder to do.