3 Replies Latest reply on Jul 23, 2007 7:13 PM by talekar

NPE in BusinessProcessContext

talekar Jul 20, 2007 9:28 PM

Hi,
I have a simple process:

<process-definition name="SimpleWorkflow">
 <start-state name="start">
 <transition to="end"></transition>
 </start-state>

 <end-state name="end"></end-state>
</process-definition>

This is started from the following stateful bean:

@Stateful
@Name("SimpleWorkflowManager")
public class SimpleWorkflowManagerImpl implements SimpleWorkflowManager, Serializable {

 private static final long serialVersionUID = 1L;

 @Logger
 private static Log LOG;

 @PersistenceContext(type = PersistenceContextType.EXTENDED)
 private EntityManager entityManager;

 @CreateProcess(definition = "SimpleWorkflow")
 public void begin() {
 LOG.debug("begin");
 LOG.debug("end");
 }

 @Remove
 @Destroy
 public void destroy() {
 }
}

Called from the following page:

!DOCTYPE composition PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
 xmlns:s="http://jboss.com/products/seam/taglib"
 xmlns:ui="http://java.sun.com/jsf/facelets"
 xmlns:f="http://java.sun.com/jsf/core"
 xmlns:h="http://java.sun.com/jsf/html"
 xmlns:rich="http://richfaces.ajax4jsf.org/rich"
 template="../layout/template.xhtml">
 <ui:define name="body">
 <h:messages styleClass="message" />
 <s:link action="#{SimpleWorkflowManager.begin}"
 value="Start Simple Workflow" />
 <f:view>
 <h:form id="list">
 <div>
 <rich:dataTable value="#{taskInstanceList}" var="task">
 <rich:column>
 <f:facet name="header">
 <h:outputText value="Name" />
 </f:facet>
 <h:outputText value="#{task.name}" />
 </rich:column>
 <rich:column>
 <f:facet name="header">
 <h:outputText value="Description" />
 </f:facet>
 <h:outputText value="#{task.description}" />
 </rich:column>
 </rich:dataTable>
 </div>
 </h:form>
 </f:view>
 </ui:define>
</ui:composition>

And I get the following error after clicking the link:

21:17:55,957 ERROR [SeamPhaseListener.afterPhase] uncaught exception
java.lang.NullPointerException
 at org.jboss.seam.contexts.BusinessProcessContext.getNamesFromContext(BusinessProcessContext.java:109)
 at org.jboss.seam.contexts.BusinessProcessContext.getNames(BusinessProcessContext.java:92)
 at org.jboss.seam.contexts.Contexts.destroy(Contexts.java:220)
 at org.jboss.seam.contexts.Lifecycle.flushAndDestroyContexts(Lifecycle.java:404)
 at org.jboss.seam.contexts.Lifecycle.endRequest(Lifecycle.java:315)
 at org.jboss.seam.jsf.AbstractSeamPhaseListener.afterRender(AbstractSeamPhaseListener.java:256)
 at org.jboss.seam.jsf.SeamPhaseListener.afterPhase(SeamPhaseListener.java:115)
 at org.apache.myfaces.lifecycle.PhaseListenerManager.informPhaseListenersAfter(PhaseListenerManager.java:89)
 at org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:391)
 at javax.faces.webapp.FacesServlet.service(FacesServlet.java:138)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
 at org.jboss.seam.web.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:63)
 at org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:57)
 at org.jboss.seam.web.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:49)
 at org.jboss.seam.debug.hot.HotDeployFilter.doFilter(HotDeployFilter.java:60)
 at org.jboss.seam.web.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:49)
 at org.jboss.seam.web.RedirectFilter.doFilter(RedirectFilter.java:45)
 at org.jboss.seam.web.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:49)
 at org.jboss.seam.web.MultipartFilter.doFilter(MultipartFilter.java:79)
 at org.jboss.seam.web.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:49)
 at org.jboss.seam.web.SeamFilter.doFilter(SeamFilter.java:84)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
 at org.ajax4jsf.framework.ajax.xmlfilter.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:96)
 at org.ajax4jsf.framework.ajax.xmlfilter.BaseFilter.doFilter(BaseFilter.java:220)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
 at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
 at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:175)
 at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:432)
 at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:74)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
 at org.jboss.web.tomcat.tc5.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:156)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
 at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
 at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
 at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
 at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:112)
 at java.lang.Thread.run(Thread.java:619)
21:17:55,958 ERROR [SeamPhaseListener.afterPhase] swallowing exception
java.lang.NullPointerException
 at org.jboss.seam.contexts.BusinessProcessContext.getNamesFromContext(BusinessProcessContext.java:109)
 at org.jboss.seam.contexts.BusinessProcessContext.getNames(BusinessProcessContext.java:92)
 at org.jboss.seam.contexts.Contexts.destroy(Contexts.java:220)
 at org.jboss.seam.contexts.Lifecycle.flushAndDestroyContexts(Lifecycle.java:404)
 at org.jboss.seam.contexts.Lifecycle.endRequest(Lifecycle.java:315)
 at org.jboss.seam.jsf.AbstractSeamPhaseListener.afterRender(AbstractSeamPhaseListener.java:256)
 at org.jboss.seam.jsf.SeamPhaseListener.afterPhase(SeamPhaseListener.java:115)
 at org.apache.myfaces.lifecycle.PhaseListenerManager.informPhaseListenersAfter(PhaseListenerManager.java:89)
 at org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:391)
 at javax.faces.webapp.FacesServlet.service(FacesServlet.java:138)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
 at org.jboss.seam.web.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:63)
 at org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:57)
 at org.jboss.seam.web.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:49)
 at org.jboss.seam.debug.hot.HotDeployFilter.doFilter(HotDeployFilter.java:60)
 at org.jboss.seam.web.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:49)
 at org.jboss.seam.web.RedirectFilter.doFilter(RedirectFilter.java:45)
 at org.jboss.seam.web.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:49)
 at org.jboss.seam.web.MultipartFilter.doFilter(MultipartFilter.java:79)
 at org.jboss.seam.web.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:49)
 at org.jboss.seam.web.SeamFilter.doFilter(SeamFilter.java:84)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
 at org.ajax4jsf.framework.ajax.xmlfilter.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:96)
 at org.ajax4jsf.framework.ajax.xmlfilter.BaseFilter.doFilter(BaseFilter.java:220)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
 at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
 at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:175)
 at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:432)
 at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:74)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
 at org.jboss.web.tomcat.tc5.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:156)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
 at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
 at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
 at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
 at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:112)
 at java.lang.Thread.run(Thread.java:619)

Thanks in advance.

1. Re: NPE in BusinessProcessContext

gavin.king Jul 21, 2007 6:47 PM (in response to talekar)

What version of Seam is this?

please put the Seam source into your sourcepath and debug into BusinessProcessContext to find the cause.
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2. Re: NPE in BusinessProcessContext

talekar Jul 23, 2007 10:04 AM (in response to talekar)

Seam 1.2.1.GA

The NPE is caused by

context.getVariables()

returning null at line number 109 in BusinessProcessContext.

 98 private Set<String> getNamesFromContext() {^M
 99 //TODO: note that this is called from Contexts.destroy(), ^M
 100 // after the Seam-managed txn was committed, but ^M
 101 // this implementation requires a hit to the database!^M
 102 HashSet<String> results = new HashSet<String>();^M
 103 org.jbpm.taskmgmt.exe.TaskInstance taskInstance = getTaskInstance();^M
 104 if (taskInstance==null)^M
 105 {^M
 106 ContextInstance context = getContextInstance();^M
 107 if ( context!=null ) ^M
 108 {^M
 109 results.addAll( context.getVariables().keySet() );^M
 110 }^M
 111 }^M
 112 else^M
 113 {^M
 114 results.addAll( taskInstance.getVariables().keySet() );^M
 115 }^M
 116 return results;^M
 117 }^M

This method is called when the context is destoryed.

Should line 107 be changed to:

 107 if ( context!=null && context.getVariables()!=null ) ^M

(Sorry about the ^M) Thanks

3. Re: NPE in BusinessProcessContext

talekar Jul 23, 2007 7:13 PM (in response to talekar)

Upgrading to jBPM 3.2.1 seems to fix this issue. Thanks for your help.
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