Nullpointer Exception while accessing Seam Component

[mcclurexl]

Hello,

I'm working for a simple Pageflow, realised in Seam, for a while. I thougt I got it running but something is missing.
When accessing a Seam Component over a jsp-file like:

<h:outputText value="#{purchaseOrder1.number}"/>

the function getNumber() in the component-class PurchaseOrder1 is called and I get the error-message from the browser:

javax.servlet.ServletException: Cannot get value for expression '#{purchaseOrder1.number}'
javax.faces.webapp.FacesServlet.service(FacesServlet.java:121)
org.jboss.seam.servlet.SeamRedirectFilter.doFilter(SeamRedirectFilter.java:23)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)

and the app-server says:

16:44:37,062 ERROR [STDERR] java.lang.NullPointerException
16:44:37,062 ERROR [STDERR] at org.jboss.seam.core.Pageflow.begin(Pageflow.java:191)
16:44:37,062 ERROR [STDERR] at org.jboss.seam.interceptors.ConversationInter
ceptor.beginNavigation(ConversationInterceptor.java:200)
16:44:37,062 ERROR [STDERR] at org.jboss.seam.interceptors.ConversationInter
ceptor.beginConversation(ConversationInterceptor.java:186)
16:44:37,062 ERROR [STDERR] at org.jboss.seam.interceptors.ConversationInter
ceptor.beginConversationIfNecessary(ConversationInterceptor.java:146)
16:44:37,062 ERROR [STDERR] at org.jboss.seam.interceptors.ConversationInter
ceptor.endOrBeginLongRunningConversation(ConversationInterceptor.java:70)
16:44:37,062 ERROR [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke0(
Native Method)

and many more. My code is oriented on the numberguess-example. Without calling the seam-component the jsp-site starts very well with URI-mapping

http://localhost:8080/seam-purchaseOrder1/purchaseOrder1.seam

but without initiating the pageflow.

Thanks for your help,
Regards Frank

[gavin.king]

What version of Seam is this?

please show the whole stack trace.

[mcclurexl]

I'm using version 1.0.00.CR3.
Whole stacktrace of the browser (IE6):

javax.servlet.ServletException: Cannot get value for expression '#{purchaseOrder1.number}'
javax.faces.webapp.FacesServlet.service(FacesServlet.java:121)
org.jboss.seam.servlet.SeamRedirectFilter.doFilter(SeamRedirectFilter.java:23)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)


root cause

javax.faces.FacesException: Cannot get value for expression '#{purchaseOrder1.number}'
org.apache.myfaces.context.servlet.ServletExternalContextImpl.dispatch(ServletExternalContextImpl.java:421)
org.apache.myfaces.application.jsp.JspViewHandlerImpl.renderView(JspViewHandlerImpl.java:234)
org.jboss.seam.jsf.SeamViewHandler.renderView(SeamViewHandler.java:59)
org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:352)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:107)
org.jboss.seam.servlet.SeamRedirectFilter.doFilter(SeamRedirectFilter.java:23)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)

whole stacktrace of jboss AS (hope this works):

17:20:08,562 ERROR [STDERR] java.lang.NullPointerException
17:20:08,562 ERROR [STDERR] at org.jboss.seam.core.Pageflow.begin(Pageflow.java:191)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.ConversationInter
ceptor.beginNavigation(ConversationInterceptor.java:200)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.ConversationInter
ceptor.beginConversation(ConversationInterceptor.java:186)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.ConversationInter
ceptor.beginConversationIfNecessary(ConversationInterceptor.java:146)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.ConversationInter
ceptor.endOrBeginLongRunningConversation(ConversationInterceptor.java:70)
17:20:08,562 ERROR [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
17:20:08,562 ERROR [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke(N
ativeMethodAccessorImpl.java:39)
17:20:08,562 ERROR [STDERR] at sun.reflect.DelegatingMethodAccessorImpl.invo
ke(DelegatingMethodAccessorImpl.java:25)
17:20:08,562 ERROR [STDERR] at java.lang.reflect.Method.invoke(Method.java:585)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:87)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.BusinessProcessInterceptor.manageBusinessProcessContext(BusinessProcessInterceptor.java:60)
17:20:08,562 ERROR [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
17:20:08,562 ERROR [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
17:20:08,562 ERROR [STDERR] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
17:20:08,562 ERROR [STDERR] at java.lang.reflect.Method.invoke(Method.java:585)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:87)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.TransactionInterc
eptor.doInTransactionIfNecessary(TransactionInterceptor.java:34)
17:20:08,562 ERROR [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
17:20:08,562 ERROR [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
17:20:08,562 ERROR [STDERR] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
17:20:08,562 ERROR [STDERR] at java.lang.reflect.Method.invoke(Method.java:585)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:87)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.RemoveInterceptor.removeIfNecessary(RemoveInterceptor.java:39)
17:20:08,562 ERROR [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
17:20:08,562 ERROR [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
17:20:08,562 ERROR [STDERR] at sun.reflect.DelegatingMethodAccessorImpl.invo
ke(DelegatingMethodAccessorImpl.java:25)
17:20:08,562 ERROR [STDERR] at java.lang.reflect.Method.invoke(Method.java:585)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:87)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.ejb.SeamInterceptor.aroundInvokeInContexts(SeamInterceptor.java:73)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.ejb.SeamInterceptor.aroundInvoke(SeamInterceptor.java:45)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.JavaBeanInterceptor.interceptInvocation(JavaBeanInterceptor.java:51)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.interceptors.JavaBeanInterceptor.intercept(JavaBeanInterceptor.java:39)
17:20:08,562 ERROR [STDERR] at com.jaxfront.seam.PurchaseOrder1$$EnhancerByCGLIB$$71ee1296.begin(<generated>)
17:20:08,562 ERROR [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
17:20:08,562 ERROR [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
17:20:08,562 ERROR [STDERR] at sun.reflect.DelegatingMethodAccessorImpl.invo
ke(DelegatingMethodAccessorImpl.java:25)
17:20:08,562 ERROR [STDERR] at java.lang.reflect.Method.invoke(Method.java:585)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.util.Reflections.invokeAndWrap(Reflections.java:32)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.Component.callComponentMethod(Component.java:1239)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.Component.callCreateMethod(Component.java:1227)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.Component.newInstance(Component.java:1216)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.Component.getInstance(Component.java:1168)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.Component.getInstance(Component.java:1151)
17:20:08,562 ERROR [STDERR] at org.jboss.seam.jsf.SeamVariableResolver.resolveVariable(SeamVariableResolver.java:44)
17:20:08,562 ERROR [STDERR] at org.apache.myfaces.el.ValueBindingImpl$ELVari
ableResolver.resolveVariable(ValueBindingImpl.java:569)
17:20:08,562 ERROR [STDERR] at org.apache.commons.el.NamedValue.evaluate(NamedValue.java:124)
17:20:08,562 ERROR [STDERR] at org.apache.commons.el.ComplexValue.evaluate(ComplexValue.java:140)
17:20:08,562 ERROR [STDERR] at org.apache.myfaces.el.ValueBindingImpl.getValue(ValueBindingImpl.java:378)
17:20:08,578 ERROR [STDERR] at javax.faces.component.UIOutput.getValue(UIOutput.java:75)
17:20:08,578 ERROR [STDERR] at org.apache.myfaces.renderkit.RendererUtils.getStringValue(RendererUtils.java:225)
17:20:08,578 ERROR [STDERR] at org.apache.myfaces.renderkit.html.HtmlTextRendererBase.renderOutput(HtmlTextRendererBase.java:65)
17:20:08,578 ERROR [STDERR] at org.apache.myfaces.renderkit.html.HtmlTextRendererBase.encodeEnd(HtmlTextRendererBase.java:53)
17:20:08,578 ERROR [STDERR] at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:331)
17:20:08,578 ERROR [STDERR] at javax.faces.webapp.UIComponentTag.encodeEnd(UIComponentTag.java:349)
17:20:08,578 ERROR [STDERR] at javax.faces.webapp.UIComponentTag.doEndTag(UIComponentTag.java:253)
17:20:08,578 ERROR [STDERR] at org.apache.jsp.purchaseOrder1_jsp._jspx_meth_h_outputText_0(purchaseOrder1_jsp.java:166)
17:20:08,578 ERROR [STDERR] at org.apache.jsp.purchaseOrder1_jsp._jspx_meth_h_form_0(purchaseOrder1_jsp.java:137)
17:20:08,578 ERROR [STDERR] at org.apache.jsp.purchaseOrder1_jsp._jspx_meth_f_view_0(purchaseOrder1_jsp.java:105)
17:20:08,578 ERROR [STDERR] at org.apache.jsp.purchaseOrder1_jsp._jspService(purchaseOrder1_jsp.java:69)
17:20:08,578 ERROR [STDERR] at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
17:20:08,578 ERROR [STDERR] at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
17:20:08,578 ERROR [STDERR] at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
17:20:08,578 ERROR [STDERR] at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
17:20:08,578 ERROR [STDERR] at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
17:20:08,578 ERROR [STDERR] at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:672)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:463)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:398)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:301)
17:20:08,578 ERROR [STDERR] at org.apache.myfaces.context.servlet.ServletExternalContextImpl.dispatch(ServletExternalContextImpl.java:415)
17:20:08,578 ERROR [STDERR] at org.apache.myfaces.application.jsp.JspViewHandlerImpl.renderView(JspViewHandlerImpl.java:234)
17:20:08,578 ERROR [STDERR] at org.jboss.seam.jsf.SeamViewHandler.renderView(SeamViewHandler.java:59)
17:20:08,578 ERROR [STDERR] at org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:352)
17:20:08,578 ERROR [STDERR] at javax.faces.webapp.FacesServlet.service(FacesServlet.java:107)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
17:20:08,578 ERROR [STDERR] at org.jboss.seam.servlet.SeamRedirectFilter.doFilter(SeamRedirectFilter.java:23)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
17:20:08,578 ERROR [STDERR] at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
17:20:08,578 ERROR [STDERR] at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:175)
17:20:08,578 ERROR [STDERR] at org.jboss.web.tomcat.security.JaccContextValv
e.invoke(JaccContextValve.java:74)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
17:20:08,578 ERROR [STDERR] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
17:20:08,578 ERROR [STDERR] at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
17:20:08,578 ERROR [STDERR] at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
17:20:08,578 ERROR [STDERR] at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
17:20:08,578 ERROR [STDERR] at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:112)
17:20:08,578 ERROR [STDERR] at java.lang.Thread.run(Thread.java:595)
17:20:08,578 ERROR [[jsp]] Servlet.service() for servlet jsp threw exception
javax.faces.el.EvaluationException: Cannot get value for expression '#{purchaseOrder1.number}' at org.apache.myfaces.el.ValueBindingImpl.getValue(ValueBindingImpl.java
:397)
at javax.faces.component.UIOutput.getValue(UIOutput.java:75)
at org.apache.myfaces.renderkit.RendererUtils.getStringValue(RendererUtils.java:225)
at org.apache.myfaces.renderkit.html.HtmlTextRendererBase.renderOutput(HtmlTextRendererBase.java:65)
at org.apache.myfaces.renderkit.html.HtmlTextRendererBase.encodeEnd(HtmlTextRendererBase.java:53)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:331)
at javax.faces.webapp.UIComponentTag.encodeEnd(UIComponentTag.java:349)
at javax.faces.webapp.UIComponentTag.doEndTag(UIComponentTag.java:253)
at org.apache.jsp.purchaseOrder1_jsp._jspx_meth_h_outputText_0(purchaseO
rder1_jsp.java:166)
at org.apache.jsp.purchaseOrder1_jsp._jspx_meth_h_form_0(purchaseOrder1_
jsp.java:137)
at org.apache.jsp.purchaseOrder1_jsp._jspx_meth_f_view_0(purchaseOrder1_
jsp.java:105)
at org.apache.jsp.purchaseOrder1_jsp._jspService(purchaseOrder1_jsp.java:69)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:3
14)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
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 org.apache.myfaces.context.servlet.ServletExternalContextImpl.dispatch(ServletExternalContextImpl.java:415)
at org.apache.myfaces.application.jsp.JspViewHandlerImpl.renderView(JspViewHandlerImpl.java:234)
at org.jboss.seam.jsf.SeamViewHandler.renderView(SeamViewHandler.java:59)
at org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:352)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.jboss.seam.servlet.SeamRedirectFilter.doFilter(SeamRedirectFilter.java:23)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
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.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:175)
at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:74)
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.p
rocessConnection(Http11BaseProtocol.java:664)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:112)
at java.lang.Thread.run(Thread.java:595)
Caused by: java.lang.NullPointerException
at org.jboss.seam.core.Pageflow.begin(Pageflow.java:191)
at org.jboss.seam.interceptors.ConversationInterceptor.beginNavigation(ConversationInterceptor.java:200)
at org.jboss.seam.interceptors.ConversationInterceptor.beginConversation
(ConversationInterceptor.java:186)
at org.jboss.seam.interceptors.ConversationInterceptor.beginConversationIfNecessary(ConversationInterceptor.java:146)
at org.jboss.seam.interceptors.ConversationInterceptor.endOrBeginLongRunningConversation(ConversationInterceptor.java:70)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:87)
at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
at org.jboss.seam.interceptors.BusinessProcessInterceptor.manageBusiness
ProcessContext(BusinessProcessInterceptor.java:60)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:87)
at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
at org.jboss.seam.interceptors.TransactionInterceptor.doInTransactionIfN
ecessary(TransactionInterceptor.java:34)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:87)
at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
at org.jboss.seam.interceptors.RemoveInterceptor.removeIfNecessary(RemoveInterceptor.java:39)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:87)
at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
at org.jboss.seam.ejb.SeamInterceptor.aroundInvokeInContexts(SeamInterceptor.java:73)
at org.jboss.seam.ejb.SeamInterceptor.aroundInvoke(SeamInterceptor.java:45)
at org.jboss.seam.interceptors.JavaBeanInterceptor.interceptInvocation(JavaBeanInterceptor.java:51)
at org.jboss.seam.interceptors.JavaBeanInterceptor.intercept(JavaBeanInterceptor.java:39)
at com.jaxfront.seam.PurchaseOrder1$$EnhancerByCGLIB$$71ee1296.begin(<ge
nerated>)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.
java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
at org.jboss.seam.util.Reflections.invokeAndWrap(Reflections.java:32)
at org.jboss.seam.Component.callComponentMethod(Component.java:1239)
at org.jboss.seam.Component.callCreateMethod(Component.java:1227)
at org.jboss.seam.Component.newInstance(Component.java:1216)
at org.jboss.seam.Component.getInstance(Component.java:1168)
at org.jboss.seam.Component.getInstance(Component.java:1151)
at org.jboss.seam.jsf.SeamVariableResolver.resolveVariable(SeamVariableResolver.java:44)
at org.apache.myfaces.el.ValueBindingImpl$ELVariableResolver.resolveVari
able(ValueBindingImpl.java:569)
at org.apache.commons.el.NamedValue.evaluate(NamedValue.java:124)
at org.apache.commons.el.ComplexValue.evaluate(ComplexValue.java:140)
at org.apache.myfaces.el.ValueBindingImpl.getValue(ValueBindingImpl.java:378)
... 49 more
17:20:08,578 ERROR [[Faces Servlet]] Servlet.service() for servlet Faces Servlet threw exception
javax.faces.FacesException: Cannot get value for expression '#{purchaseOrder1.number}'
at org.apache.myfaces.context.servlet.ServletExternalContextImpl.dispatch(ServletExternalContextImpl.java:421)
at org.apache.myfaces.application.jsp.JspViewHandlerImpl.renderView(JspViewHandlerImpl.java:234)
at org.jboss.seam.jsf.SeamViewHandler.renderView(SeamViewHandler.java:59)
at org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:352)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appl
icationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF
ilterChain.java:173)
at org.jboss.seam.servlet.SeamRedirectFilter.doFilter(SeamRedirectFilter.java:23)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appl
icationFilterChain.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.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:175)
at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:74)
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.p
rocessConnection(Http11BaseProtocol.java:664)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:112)
at java.lang.Thread.run(Thread.java:595)
Caused by: org.apache.jasper.JasperException: Cannot get value for expression '#{purchaseOrder1.number}'
at org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:510)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
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:810)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
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 org.apache.myfaces.context.servlet.ServletExternalContextImpl.dispatc
h(ServletExternalContextImpl.java:415)
... 25 more

[dwayneb]

line 191 is a comment in Pageflow 1.0.0.CR3!!!

I'd got a similar problem. The displaing exception isn't the root one. In my case, the cause was that the PageflowProcessDefinition wasn't define (=> NPE). So check if the pageflow is define :
check in web.xml :

 <context-param>
<param-name>org.jboss.seam.core.jbpm.pageflowDefinitions</param-name>
 <param-value>
 mypageflow.jpdl.xml
 </param-value>
 </context-param>

check that the name use in @begin is the same as the one used in the name attribut's of root node <pageflow-definition name="mypageflow"> of the mypageflow.jpdl.xml

check that mypageflow is accessible (eg: root of the ear)

May it could help

[mcclurexl]

Hey dwayneb,

you got it, thanks a lot. The name of the pageflow-definition in the java-class was wrong. The first letter wasn't a capitel one, rest was correct.

Greets,
Frank

[gavin.king]

I changed Seam to throw a more meaningful exception.

[davidnavara]

I had a similar problem with Seam 2.0.0 Beta. There is a seam-drools example within the package which doesn't work and ends also with NullPointerException in ConversationInterceptor.beginNavigation method.

The point is that the namespace of JBPM tags in components.xml changed.

Old components.xml section:

 <core:jbpm>
 <core:pageflow-definitions>
 <value>pageflow.jpdl.xml</value>
 </core:pageflow-definitions>
 </core:jbpm>

New components.xml section:

 <bpm:jbpm>
 <bpm:pageflow-definitions>
 <value>pageflow.jpdl.xml</value>
 </bpm:pageflow-definitions>
 </bpm:jbpm>

Even if I read Seam documentation, I overlooked the little change and spent some hours tracing it why the JBPM doesn't load.

David Navara