Re: [rules-users] NullpointerException in Multithreading at KnowledgeBuilde

Hi everyone, I'm using Drools in a multithreaded environment where I need to create multiple KnowledgeBuilders, which each contains a different rule. But if I want to add the rule to the builder I'm getting the following exception: ----------------------------------------------------------------------- Exception in thread "ECJ Evaluation Thread 3" java.lang.NullPointerException at org.drools.rule.builder.dialect.mvel.MVELDialect.addStaticPackageImport(MVELDialect.java:416) at org.drools.rule.builder.dialect.mvel.MVELDialect.addStaticImport(MVELDialect.java:372) at org.drools.compiler.DialectCompiletimeRegistry.addStaticImport(DialectCompiletimeRegistry.java:96) at org.drools.compiler.PackageRegistry.addStaticImport(PackageRegistry.java:94) at org.drools.compiler.PackageBuilder.processFunctions(PackageBuilder.java:1270) at org.drools.compiler.PackageBuilder.processOtherDeclarations(PackageBuilder.java:1225) at org.drools.compiler.PackageBuilder.mergePackage(PackageBuilder.java:1220) at org.drools.compiler.PackageBuilder.addPackage(PackageBuilder.java:829) at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:467) at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:673) at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:45) at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:34) at rulevolution.RulEvolution.getSession(RulEvolution.java:195) at rulevolution.RulEvolution.runDrools(RulEvolution.java:159) at rulevolution.RulEvolution.evaluate(RulEvolution.java:106) at ec.simple.SimpleEvaluator.evalPopChunk(SimpleEvaluator.java:259) at ec.simple.SimpleEvaluator$SimpleEvaluatorThreadCG.run(SimpleEvaluator.java:341) at ec.util.ThreadPool$PoolThread.run(ThreadPool.java:57) ----------------------------------------------------------------------- I'm getting the same exception in each thread so I only copied thread 3. The Code I'm using to initiate my Session is the following: ----------------------------------------------------------------------- public synchronized StatefulKnowledgeSession getSession(byte[] array){ KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(); kbuilder.add(ResourceFactory.newByteArrayResource(array), ResourceType.DRL); KnowledgeBuilderErrors errors = kbuilder.getErrors(); if (!errors.isEmpty()) { for (KnowledgeBuilderError knowledgeBuilderError : errors) { logger.log(Level.SEVERE, "error while parsing grammmars in "+knowledgeBuilderError.getResource().toString()+":: " + knowledgeBuilderError.getMessage()); } try { throw new Exception(); } catch (Exception e) { e.printStackTrace(); } } KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(); kbase.addKnowledgePackages(kbuilder.getKnowledgePackages()); return kbase.newStatefulKnowledgeSession(); } ----------------------------------------------------------------------- This method is called for each Rule I create one time. The rules are created automatically and are syntactically correct, here is an example: ----------------------------------------------------------------------- import function de.fraunhofer.scai.bio.uima.droolutils.FactChecker.*; import function de.fraunhofer.scai.bio.uima.droolutils.ODMAnswerManager.*; global org.apache.uima.util.impl.JSR47Logger_impl log global org.apache.uima.jcas.JCas aJCas rule '2' when $0: CoreAnnotation( label_0:getActivityProvenance().toString(), getConcept().identifierSource.contains('de.cloud4health.odm.eprd.bodySide')) $1: CoreAnnotation( label_1:getActivityProvenance().toString(), getConcept().identifierSource.contains('de.cloud4health.odm.eprd.anatomy')) $2: NormalizedNamedEntity( label_2:getConcept().getPrefLabel().value, getConcept().identifierSource.contains('de.cloud4health.odm.eprd.anatomy')) eval (hasSameInstance($0, $1, $2)) eval (areEqual($0, $1, $2)) then int start = getStart($0,$1,$2); int ende = getEnd($0,$1,$2); String attribute = label_0+label_1+label_2; log.log(Level.FINE, 'Inserted de.cloud4health.odm.eprd.itemGroup.anatomy'); insert(annotate(aJCas, 'de.cloud4health.odm.eprd.itemGroup.anatomy', attribute, start, ende, null, null)); end ----------------------------------------------------------------------- I appreciate any help. Thank you. Bojan _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users