KieBase Deserialization: NullPointerException --------------------------------------------- Key: DROOLS-2552 URL: https://issues.jboss.org/browse/DROOLS-2552 Project: Drools Issue Type: Bug Components: core engine Affects Versions: 7.7.0.Final Environment: Windows 7, Java 1.8, Drools 7.7.0.Final, jBPM 7.7.0.Final Reporter: Florian Braun Assignee: Mario Fusco Priority: Critical I have run into an issue with the KieBase serialization throwing a NullPointerException when using exists and parentheses around an or when rules are in a RuleFlowGroup. Example rules: package com.sample.rules rule "Your First Rule" ruleflow-group "group1" when exists ( String(this == "Hello") or String(this == "World") ) then System.out.println("Hello or World"); end rule "Your Second Rule" ruleflow-group "group1" when $string: String(this == "Hello World") then System.out.println($string); end Having the first rule wrap the or in () will cause a deserialization NPE: Exception in thread "main" java.lang.NullPointerException at org.drools.core.common.BaseNode.getSinks(BaseNode.java:241) at org.drools.core.impl.KnowledgeBaseImpl.rewireNodeAfterDeserialization(KnowledgeBaseImpl.java:494) at org.drools.core.impl.KnowledgeBaseImpl.rewireNodeAfterDeserialization(KnowledgeBaseImpl.java:511) at org.drools.core.impl.KnowledgeBaseImpl.rewireNodeAfterDeserialization(KnowledgeBaseImpl.java:511) at org.drools.core.impl.KnowledgeBaseImpl.rewireNodeAfterDeserialization(KnowledgeBaseImpl.java:511) at org.drools.core.impl.KnowledgeBaseImpl.rewireReteAfterDeserialization(KnowledgeBaseImpl.java:489) at org.drools.core.impl.KnowledgeBaseImpl.readExternal(KnowledgeBaseImpl.java:483) .... Some testing shows this: If the first rule is on its own then this error does *not* occur. If the first rule does not use () the error does *not* occur. This of course means that the rule behaves differently If the rules are not in an rfg this error does *not* occur