NullpointerException when trying to reuse KnowledgePackage into a new KnowledgeBase ----------------------------------------------------------------------------------- Key: DROOLS-1158 URL: https://issues.jboss.org/browse/DROOLS-1158 Project: Drools Issue Type: Bug Affects Versions: 6.3.0.Final, 6.4.0.Final Reporter: Juan Carlos Garcia Assignee: Matteo Mortari Attachments: drools-reusepackage.tar, screenshot-1.png Having a set of DecisionTables which KnowledgePackages are cached in our application, after we detect a change in any of those XLS files, we build a KnowledgePackages from it, and then try to create a new KnowledgeBase with the new KnowledgePackages + the rest of the cached one that that were not modified, but it fails with a NPE internally in Drools (6.3.0 and 6.4.0) This is not a problem for the drools version (6.0.1.Final) that we currently uses using in production. After debugging and putting a breakpoint into the *MvelConstraint.java:619*, it shows that it is trying to look for a packageName which hasn't being loaded yet in the new kbase (but belong to others XLS). I have attached a project with a testcase that shows the problem, it has 2 DecisionTable which i had to cut down a little bit (from our real files) and removes some sensitive information (replacing some of text with FOO-BAR). {code} java.lang.NullPointerException at org.drools.core.rule.constraint.MvelConstraint.equals(MvelConstraint.java:619) at org.drools.core.reteoo.AlphaNode.internalEquals(AlphaNode.java:199) at org.drools.core.common.BaseNode.thisNodeEquals(BaseNode.java:194) at org.drools.core.reteoo.CompositeObjectSinkAdapter.getMatchingNode(CompositeObjectSinkAdapter.java:531) at org.drools.core.reteoo.builder.BuildUtils.attachNode(BuildUtils.java:121) at org.drools.core.reteoo.builder.PatternBuilder.buildAlphaNodeChain(PatternBuilder.java:332) at org.drools.core.reteoo.builder.PatternBuilder.attachAlphaNodes(PatternBuilder.java:313) at org.drools.core.reteoo.builder.PatternBuilder.attachPattern(PatternBuilder.java:130) at org.drools.core.reteoo.builder.PatternBuilder.build(PatternBuilder.java:78) at org.drools.core.reteoo.builder.GroupElementBuilder$AndBuilder.build(GroupElementBuilder.java:108) at org.drools.core.reteoo.builder.GroupElementBuilder.build(GroupElementBuilder.java:68) at org.drools.core.reteoo.builder.ReteooRuleBuilder.addSubRule(ReteooRuleBuilder.java:161) at org.drools.core.reteoo.builder.ReteooRuleBuilder.addRule(ReteooRuleBuilder.java:133) at org.drools.core.reteoo.ReteooBuilder.addRule(ReteooBuilder.java:106) at org.drools.core.impl.KnowledgeBaseImpl.addRule(KnowledgeBaseImpl.java:1567) at org.drools.core.impl.KnowledgeBaseImpl.addRule(KnowledgeBaseImpl.java:1547) at org.drools.core.impl.KnowledgeBaseImpl.internalAddPackages(KnowledgeBaseImpl.java:920) at org.drools.core.impl.KnowledgeBaseImpl.access$000(KnowledgeBaseImpl.java:117) at org.drools.core.impl.KnowledgeBaseImpl$1.run(KnowledgeBaseImpl.java:708) at org.drools.core.impl.KnowledgeBaseImpl.enqueueModification(KnowledgeBaseImpl.java:716) at org.drools.core.impl.KnowledgeBaseImpl.addPackages(KnowledgeBaseImpl.java:705) at org.drools.core.impl.KnowledgeBaseImpl.addKnowledgePackages(KnowledgeBaseImpl.java:273) at org.drools.impl.adapters.KnowledgeBaseAdapter.addKnowledgePackages(KnowledgeBaseAdapter.java:62) at bug.demo.BugReloadableDecisionTableTest.addRuleSetToKnowledgeBase(BugReloadableDecisionTableTest.java:63) at bug.demo.BugReloadableDecisionTableTest.testReuseKnowledgePackage(BugReloadableDecisionTableTest.java:53) {code}