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(a)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(a)gmail.com&gt; 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.handleExcept ion(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.j ava:733) at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.j ava:699) at org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeS essionImpl.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 _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

Thanks Wolfgang! Very helpful! 发件人: rules-users-bounces(a)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. * My company develops safety-relevant SW according to the standards set forth by a body called CENELEC <http://en.wikipedia.org/wiki/European_Committee_for_Electrotechnical_Standa rdization> . The (for us) essential standard refutes the use of any language that hasn't a formal definition. I've never found such a definition for MVEL. * A considerable number of Drools bugs are, in fact, MVEL bugs. * Bug fixing of MVEL by its author is tardy (as I've been told by members of the Drools team), and therefore: * The Drools project had to adopt the strategy of issuing their own release of MVEL, to be bundled with Drools releases. 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(a)gmail.com&gt; 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(a)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(a)gmail.com&gt; 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.handleExcept ion(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.j ava:733) at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.j ava:699) at org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeS essionImpl.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 _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users