[rules-users] Interesting null pointer exception when inserting afact.

Wed Mar 12 15:28:27 EDT 2008

Jason Partyka wrote:
> It looks like the bug is still in there.
>  
> I am attempting to resolve it myself, but in order to do so I need to 
> go into the MVEL code, but the mvel jar that is included as part of 
> the drools classpath container (within eclipse) is just mvel14.jar. So 
> I'm not sure where the source is or what version of MVEL source I 
> should be attaching. I realize that the source-location thing is just 
> an Eclipse issue, but I thought I'd let you know right away that it 
> looks like it's still there.
We strip jar version numbers to make deployment with Eclipse easier. If 
you look at parent pom.xml it will tell you the version of MVEL used.
>  
> Anywhere you can point me to that would help with making sure I'm 
> looking the right code.
>  
> Thanks,
> Jason
> ------------------------------------------------------------------------
> *From:* rules-users-bounces at lists.jboss.org 
> [rules-users-bounces at lists.jboss.org] On Behalf Of Mark Proctor 
> [mproctor at codehaus.org]
> *Sent:* Monday, March 10, 2008 8:17 AM
> *To:* Rules Users List
> *Subject:* Re: [rules-users] Interesting null pointer exception when 
> inserting afact.
>
> please check with 4.0.x, which will be in 4.0.5 this week, and let us 
> know if this is fixed or not. But hurry we are releasing 4.0.5 very soon:
> http://anonsvn.labs.jboss.com/labs/jbossrules/branches/4.0.x/
>
> Mark
> Jason Partyka wrote:
>> I can give this a shot, but the reason why you suggest this is not 
>> obvious to me.
>>  
>> Have you encountered this problem yourself?
>>  
>> -Jason
>>  
>>  
>>  
>> ------------------------------------------------------------------------
>> *From:* rules-users-bounces at lists.jboss.org 
>> [rules-users-bounces at lists.jboss.org] On Behalf Of Anstis, Michael 
>> (M.) [manstis1 at ford.com]
>> *Sent:* Monday, March 10, 2008 5:06 AM
>> *To:* Rules Users List
>> *Subject:* RE: [rules-users] Interesting null pointer exception when 
>> inserting afact.
>>
>> I'm no expert but recall there can be problems running "long 
>> running" (subjective) code from AWT's worker thread.
>>  
>> I thought it was good practice to run your "application code" in a 
>> worker thread. This was the first google hit I had on the matter. 
>>  
>> http://www.cs.helsinki.fi/u/vihavain/k03/Java/JavathreadsandGUI.html
>>  
>> Cheers,
>>  
>> Mike
>>
>>     ------------------------------------------------------------------------
>>     *From:* rules-users-bounces at lists.jboss.org
>>     [mailto:rules-users-bounces at lists.jboss.org] *On Behalf Of *Edson
>>     Tirelli
>>     *Sent:* 08 March 2008 13:15
>>     *To:* Rules Users List
>>     *Subject:* Re: [rules-users] Interesting null pointer exception
>>     when inserting afact.
>>
>>
>>        Jason,
>>
>>        Can you please isolate and show us the rule that is creating
>>     the problem? It is happening either in a eval() statement or in a
>>     nested property access.
>>
>>         []s
>>         Edson
>>
>>     2008/3/7, Jason Partyka <Jason.Partyka at hightowerinc.com
>>     <mailto:Jason.Partyka at hightowerinc.com>>:
>>
>>         Hi,
>>
>>         This is in relation to drools 4.0.4
>>
>>         I have an interesting problem. I am getting a null pointer
>>         exception when I am inserting a fact into a StatefulSession
>>         object. What is odd about this NPE is that, as far as I can
>>         tell (and I have inserted a breakpoint right before I insert
>>         the fact) that all the properties in the object are
>>         initialized, and there are no rules accessing any thing that
>>         could be null.
>>
>>         So here's my exception trace (just first few lines to get
>>         context):
>>
>>         Exception in thread "AWT-EventQueue-0"
>>         org.drools.RuntimeDroolsException: java.lang.NullPointerException
>>           at
>>         org.drools.rule.EvalCondition.isAllowed(EvalCondition.java:76)
>>           at
>>         org.drools.reteoo.EvalConditionNode.assertTuple(EvalConditionNode.java:145)
>>           at
>>         org.drools.reteoo.SingleTupleSinkAdapter.createAndPropagateAssertTuple(SingleTupleSinkAdapter.java:55)
>>           at
>>         org.drools.reteoo.LeftInputAdapterNode.assertObject(LeftInputAdapterNode.java:116)
>>           at
>>         org.drools.reteoo.SingleObjectSinkAdapter.propagateAssertObject(SingleObjectSinkAdapter.java:22)
>>           at
>>         org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:153)
>>           at org.drools.reteoo.Rete.assertObject(Rete.java:177)
>>           at
>>         org.drools.reteoo.ReteooRuleBase.assertObject(ReteooRuleBase.java:192)
>>           at
>>         org.drools.reteoo.ReteooWorkingMemory.doInsert(ReteooWorkingMemory.java:71)
>>           at
>>         org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:886)
>>           at
>>         org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:858)
>>           at
>>         org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:659)
>>           at
>>         com.hightower.drools.executablerules.Rules.setTemplate(Rules.java:112)
>>         ....
>>         Caused by: java.lang.NullPointerException
>>           at
>>         org.drools.base.mvel.MVELEvalExpression.evaluate(MVELEvalExpression.java:39)
>>           at
>>         org.drools.rule.EvalCondition.isAllowed(EvalCondition.java:72)
>>           ... 39 more
>>
>>
>>         (that setTemplate method is not a drools template)
>>
>>         Any ideas?
>>
>>         Thanks,
>>         Jason
>>
>>         _______________________________________________
>>         rules-users mailing list
>>         rules-users at lists.jboss.org <mailto:rules-users at lists.jboss.org>
>>         https://lists.jboss.org/mailman/listinfo/rules-users
>>
>>
>>
>>
>>     -- 
>>       Edson Tirelli
>>       JBoss Drools Core Development
>>       Office: +55 11 3529-6000
>>       Mobile: +55 11 9287-5646
>>       JBoss, a division of Red Hat @ www.jboss.com
>>     <http://www.jboss.com> 
>>
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> rules-users mailing list
>> rules-users at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/rules-users
>>   
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> rules-users mailing list
> rules-users at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
>   

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.jboss.org/pipermail/rules-users/attachments/20080312/9a62e4e2/attachment.html