[rules-users] Drools Flow : Persistence :- Getting Null Pointer Exception in JPAWorkItemManager.java

[Pardeep.Ruhil at lntinfotech.com]

Hi Kris,
Thanks for your reply.
This problem was solved. It was because I was not completing the workItem 
using the kession object. Because of that I was getting NPE in 
JPAWorkItemManager.java

After that when I made changes to my code I got the same exception but 
this time it is in MarshallerReaderContext.java

caused by :java.lang.NullPointerException
        at 
org.drools.marshalling.impl.MarshallerReaderContext.resolveClass(
MarshallerReaderContext.java:78)
        at java.io.ObjectInputStream.readNonProxyDesc(Unknown Source)
        at java.io.ObjectInputStream.readClassDesc(Unknown Source)
        at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
        at java.io.ObjectInputStream.readObject0(Unknown Source)
        at java.io.ObjectInputStream.readObject(Unknown Source)
        at org.drools.marshalling.impl.InputMarshaller.readWorkItem(
InputMarshaller.java:830)
        at 
org.drools.persistence.processinstance.WorkItemInfo.getWorkItem(
WorkItemInfo.java:86)
        at 
org.drools.persistence.processinstance.JPAWorkItemManager.completeWorkItem(
JPAWorkItemManager.java:91)
        at 
org.drools.command.runtime.process.CompleteWorkItemCommand.execute(
CompleteWorkItemCommand.java:46)
        at 
org.drools.command.runtime.process.CompleteWorkItemCommand.execute(
CompleteWorkItemCommand.java:12)
        at 
org.drools.persistence.session.SingleSessionCommandService.execute(
SingleSessionCommandService.java:254)
        at 
org.drools.command.impl.CommandBasedStatefulKnowledgeSession$1.completeWorkItem(
CommandBasedStatefulKnowledgeSession.java:119)
        at 
org.ofbiz.drools.event.drool.HumanWorkItemHandler.createApplication(
HumanWorkItemHandler.java:302)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at org.ofbiz.drools.event.drool.HumanWorkItemHandler.runTask(
HumanWorkItemHandler.java:257)
        at org.ofbiz.drools.event.drool.CommonDrool.commonHumanTaskMethod(
CommonDrool.java:56)
        at 
org.ofbiz.humanres.drool.CreateAndAprrove.createHrJobPostingRequest(
CreateAndAprrove.java:42)

Do you have any Idea about this why I am getting this exception.

Thanks & Regards

Pardeep Ruhil





Kris Verlaenen <kris.verlaenen at cs.kuleuven.be> 
11/09/2009 05:23 PM

To
Rules Users List <rules-users at lists.jboss.org>, 
<Pardeep.Ruhil at lntinfotech.com>
cc

Subject
Re: [rules-users] Drools Flow : Persistence :- Getting Null Pointer 
Exception in JPAWorkItemManager.java






How are you calling completeWorkItem (could you show me the entire stack
trace)?  When you use persistence, you must make sure all (asynchronous)
invocations to the engine go through the session (as that will make sure
the entity manager is created and changes get persisted afterwards).  As
a result, if your work item is completed asynchronously, you should
complete it using ksession.getWorkItemManager().completeWorkItem(..)
(and not using the WorkItemManager reference you got during
executeWorkItem(..) as that is for synchronous use only).

Kris

Quoting Pardeep.Ruhil at lntinfotech.com:

> Hi,
> When I try to run a sample test case using drools-persistence.jar it
> works 
> successfully.
> But when I try to include the persistence in my OFBiz application, I
> am 
> getting null pointer exception in class JPAWorkItemManager.java.
> 
> java.lang.NullPointerException 
>  at 
>
org.drools.persistence.processinstance.JPAWorkItemManager.completeWorkItem(
> JPAWorkItemManager.java:85).
> 
> Null Pointer is because of getting EntityManager object as NULL. In
> the 
> below line of JPAWorkItemManager.java
>   EntityManager em = (EntityManager) this.workingMemory
> .getEnvironment().get( EnvironmentName.ENTITY_MANAGER );
> the em is null.
> Because of this I am getting Null Pointer exception when it try to
> run the 
> code
>  if (workItemInfo == null) {
>                 workItemInfo = em.find(WorkItemInfo.class, id);
>         }
> 
> Can you tell me why I getting NPE when I try to run the jar file in
> my 
> application.
> While the code run successfully when I try to run sample test case
> for 
> that.
> Please help me to get through the situation.
> 
> 
> Thanks & Regards
> 
> Pardeep Ruhil
> L&T Infotech Ltd
> Mumbai
> Ph: +919820283884
> 
> Larsen & Toubro Infotech Ltd.
> www.Lntinfotech.com
> 
> This Document is classified as: 
> 
> L&T Infotech Proprietary   L&T Infotech Confidential   L&T Infotech 
> Internal Use Only   L&T Infotech General Business 
> 
> This Email may contain confidential or privileged information for the
> 
> intended recipient (s) If you are not the intended recipient, please
> do 
> not use or disseminate the information, notify the sender and delete
> it 
> from your system. 
> 
> ______________________________________________________________________




Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm

______________________________________________________________________



______________________________________________________________________
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.jboss.org/pipermail/rules-users/attachments/20091110/d3c3fad7/attachment.html