Thanks Wolfgang! Very helpful!
发件人: rules-users-bounces@lists.jboss.org
[mailto:rules-users-bounces@lists.jboss.org] 代表 Wolfgang Laun
发送时间: 2012年3月11日 2:58
收件人: Rules Users List
主题: Re: [rules-users] 答复: Adhoc NullPointer exception in rule execution
Since you ask me... It may not be
"wisdom", though...
I do not use 'dialect "mvel"' in
the rules I write. Here are some facts on which this decision is based.
There's some good reasons why MVEL has been
introduced into Drools, and why it is used when and where it is used. But I
wouldn't recommend it's use in RHS of rules just to save me the trouble of
writing the more verbose Java equivalent.
Also, I'd like to point out that MVEL bug
fixing has picked up as soon as Drools team members were available to do
so.
Cheers
Wolfgang
2012/3/10 Zhuo Li <milanello1998@gmail.com>
Yep, Wolfgang,
It’s a code issue – I just identified it… thanks. I have another
thread talking about NoClassDefFound exception. Would appreciate if you can
share your wisdom there.
Best
Abe
发件人: rules-users-bounces@lists.jboss.org
[mailto:rules-users-bounces@lists.jboss.org]
代表 Wolfgang Laun
发送时间: 2012年3月11日 1:06
收件人: Rules Users List
主题: Re: [rules-users]
Adhoc NullPointer exception in rule execution
The location of the NPE is
at com.xxx.xxx.xxx.xxx.xxx.xxx.xxx(xxx.java:634)
and that's your code, invoked from the right hand side of rule
Match.
-W
2012/3/10 Zhuo Li <milanello1998@gmail.com>
Hi, folks,
I’m using Drools 5.1, MVEL dialect, JDK 1.6
to build a OLTP system running on tomcat 6.0.28. the runtime environment is on
a cloud virtual and node profile is relatively small. We’ve noticed below run time exceptions from prod since it’s online from day one which is impacting transaction processing.
However it is happening adhoc-ly. Here I have 1 question:
1. The yellow marked lines are actually java file compiled from DRL
file. Why there is null pointer exception thrown from org.drools.common.DefaultAgenda.fireActivation?
ERROR>2012-02-25 11:42:25,071
com.xxx.xxx.xxx.xxx[DefaultQuartzScheduler_Worker-3]: Rules run time error:
org.drools.runtime.rule.ConsequenceException:
rule: Match
at
org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:916)
at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:845)
at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1056)
at
org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:733)
at
org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:699)
at
org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:218)
at com. xxx.xxx.xxx.xxx.xxx.xxx.xxx (SessionManager.java:94)
at com. xxx.xxx.xxx.xxx.xxx.xxx.yyy(SessionManagerJob.java:17)
at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
at
org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:525)
Caused by: java.lang.NullPointerException
at com.xxx.xxx.xxx.xxx.xxx.xxx.xxx(xxx.java:634)
at com.xxx.xxx.xxx.xxx.xxx.yyy.yyy(yyy.java:227)
at com.xxx.xxx.xxx.xxx.xxx.yyy.zzz(zzz.java:115)
at com.xxx.xxx.xxx.xxx.xxx.yyy.ttt(ttt.java:83)
at com.xxx.xxx.xxx.xxx.xxx.yyy.uuu(uuu.java:75)
at com. com.xxx.xxx.xxx.xxx.xxx.yyy.vvv(vvv.java:9)
at com. com.xxx.xxx.xxx.xxx.xxx.yyy.www(www.java:28)
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:906)
... 9 more
Best regards
Abe
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