Hi , We have noted another incident in our testing environment where we have noted that there is a concurrency issue with the drools and mvel version we are using where the threads are blocked for a long time resulting the application node/JVM reach an unexpected state which needed to be restarted.Could some one look into this if there is a known defect on this and if it has been resolved in a later version?. Thread[DSLFpmlDataRecordKeepingTradeViewCacheWorker:5,5,DSLFpmlDataRecordKeepingTradeViewCache] java.util.WeakHashMap.get(WeakHashMap.java:470) org.mvel2.util.ParseTools.getBestCandidate(ParseTools.java:246) org.mvel2.util.ParseTools.getBestCandidate(ParseTools.java:224) org.mvel2.compiler.PropertyVerifier.getMethod(PropertyVerifier.java:509) org.mvel2.compiler.PropertyVerifier.analyze(PropertyVerifier.java:120) org.mvel2.compiler.ExpressionCompiler.verify(ExpressionCompiler.java:381) org.mvel2.compiler.ExpressionCompiler._compile(ExpressionCompiler.java:273) org.mvel2.compiler.ExpressionCompiler.compile(ExpressionCompiler.java:62) org.mvel2.MVEL.compileExpression(MVEL.java:810) org.drools.base.mvel.MVELCompilationUnit.compile(MVELCompilationUnit.java:426) org.drools.base.mvel.MVELCompilationUnit.getCompiledExpression(MVELCompilationUnit.java:243) org.drools.base.dataproviders.MVELDataProvider.compile(MVELDataProvider.java:83) org.drools.rule.MVELDialectRuntimeData.onBeforeExecute(MVELDialectRuntimeData.java:162) org.drools.rule.DialectRuntimeRegistry.onBeforeExecute(DialectRuntimeRegistry.java:138) org.drools.common.AbstractRuleBase.readExternal(AbstractRuleBase.java:295) org.drools.reteoo.ReteooRuleBase.readExternal(ReteooRuleBase.java:223) org.drools.impl.KnowledgeBaseImpl.readExternal(KnowledgeBaseImpl.java:116) java.io.ObjectInputStream.readExternalData(ObjectInputStream.java:1835) java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1794) java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1348) java.io.ObjectInputStream.readObject(ObjectInputStream.java:370) Thread[DSLFpmlDataRecordKeepingCacheWorker:39,5,DSLFpmlDataRecordKeepingCache] java.util.WeakHashMap.expungeStaleEntries(WeakHashMap.java:386) java.util.WeakHashMap.getTable(WeakHashMap.java:417) java.util.WeakHashMap.get(WeakHashMap.java:464) org.mvel2.util.ParseTools.getBestCandidate(ParseTools.java:246) org.mvel2.util.ParseTools.getBestCandidate(ParseTools.java:224) org.mvel2.compiler.PropertyVerifier.getMethod(PropertyVerifier.java:509) org.mvel2.compiler.PropertyVerifier.analyze(PropertyVerifier.java:120) org.mvel2.compiler.ExpressionCompiler.verify(ExpressionCompiler.java:381) org.mvel2.compiler.ExpressionCompiler._compile(ExpressionCompiler.java:273) org.mvel2.compiler.ExpressionCompiler.compile(ExpressionCompiler.java:62) org.mvel2.MVEL.compileExpression(MVEL.java:810) org.drools.base.mvel.MVELCompilationUnit.compile(MVELCompilationUnit.java:426) org.drools.base.mvel.MVELCompilationUnit.getCompiledExpression(MVELCompilationUnit.java:243) org.drools.base.mvel.MVELPredicateExpression.compile(MVELPredicateExpression.java:69) org.drools.rule.MVELDialectRuntimeData.onBeforeExecute(MVELDialectRuntimeData.java:162) org.drools.rule.DialectRuntimeRegistry.onBeforeExecute(DialectRuntimeRegistry.java:138) org.drools.common.AbstractRuleBase.readExternal(AbstractRuleBase.java:295) org.drools.reteoo.ReteooRuleBase.readExternal(ReteooRuleBase.java:223) org.drools.impl.KnowledgeBaseImpl.readExternal(KnowledgeBaseImpl.java:116) java.io.ObjectInputStream.readExternalData(ObjectInputStream.java:1835) java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1794) java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1348) java.io.ObjectInputStream.readObject(ObjectInputStream.java:370) We have found a similar BUG in the drools defect database https://issues.jboss.org/i#browse/DROOLS-81 but the scenarios are bit different. In our case it has happened when we deserialize the serilized KnowledgeBaseImpl by multiple threads and it seems that the problem is due to usage of a java.util.WeakHashMap as a class variable in org.mvel2.util.ParseTools.getBestCandidate(ParseTools.java:246) Thanks & Regards, Adarsh SENIOR LEAD DEVELOPMENT SPECIALIST SCJP, SCWCD FINANCE TECHNOLOGY HSBC BANK PLC HBEU 8 Canada Square,Canary Wharf, London,E14 5HQ,United Kingdom ------------------------------------------------------ Phone +44 207914720 Mobile 07595530105 Email. adarsh.chaini(a)hsbcib.com ________________________________ From: Imran Shafiq <ishafiq(a)redhat.com&gt; To: Adarsh CHAINI/IBEU/HSBC@HSBC Date: 17/09/2013 18:55 Subject: Drools Community Issue. Hi Ardash, I've seen details of the recent issue you have experienced with the community Drools product; I was keen to contact you regarding this. We have been a strategic and global supplier to HSBC for many years, and have built our success largely on our ability to provide full enterprise services and productised versions of community products, that are fit for enterprise use. In the case of community Drools, our productised version (JBoss BRMS) provides a full testing, certification, commercial assurance eco-system, and 24*7 SLA support service - which would appear to be ideally positioned to help address issues such as that which you are currently experiencing. Ardash, given the appetite of HSBC to mitigate the risk associated with the use of community software alone, I would welcome the opportunity to have a brief initial conversation with you concerning the above. Might there be a suitable number for me to reach you in the coming days? Kind regards Imran Imran Shafiq Strategic & Global Accounts Team Red Hat UK Direct: +44 (0) 1252 362766 Mobile: +44 (0) 7506 765 287 ishafiq(a)redhat.com www.europe.redhat.com ************************************************************ HSBC Bank plc may be solicited in the course of its placement efforts for a new issue, by investment clients of the firm for whom the Bank as a firm already provides other services. It may equally decide to allocate to its own proprietary book or with an associate of HSBC Group. This represents a potential conflict of interest. HSBC Bank plc has internal arrangements designed to ensure that the firm would give unbiased and full advice to the corporate finance client about the valuation and pricing of the offering as well as internal systems, controls and procedures to identify and manage conflicts of interest. 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