Wolfgang Laun created JBRULES-3383: -------------------------------------- Summary: Order of fact retractions causes NPE Key: JBRULES-3383 URL: https://issues.jboss.org/browse/JBRULES-3383 Project: Drools Issue Type: Bug Security Level: Public (Everyone can see) Components: drools-core, drools-core (expert) Affects Versions: 5.3.0.Final Reporter: Wolfgang Laun Assignee: Mark Proctor Priority: Critical Insert one from each, the second referencing the first: class Event{ String name; } class Monitor{ Event event; String name; } The following rule runs into a NPE, except when reversing the marked lines. rule "timeout" timer( int: 10s ) when $m: Monitor( name == $name ) $e: Event($name: name) then retract( $m ); // ======================= retract( $m.getEvent() ); // ======================== end Exception in thread "main" Exception executing consequence for rule "start monitoring" in hashcode: java.lang.NullPointerException at org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39) at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1101) at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:1029) at org.drools.common.DefaultAgenda.fireUntilHalt(DefaultAgenda.java:1229) at org.drools.common.AbstractWorkingMemory.fireUntilHalt(AbstractWorkingMemory.java:753) at org.drools.common.AbstractWorkingMemory.fireUntilHalt(AbstractWorkingMemory.java:729) at org.drools.impl.StatefulKnowledgeSessionImpl.fireUntilHalt(StatefulKnowledgeSessionImpl.java:234) at hashcode.Main.execute(Main.java:148) at hashcode.Main.main(Main.java:206) Caused by: java.lang.NullPointerException at org.drools.base.hashcode.StateEvent42211789$getItemName.getValue(Unknown Source) at org.drools.base.ClassFieldReader.getValue(ClassFieldReader.java:87) at org.drools.rule.Declaration.getValue(Declaration.java:219) at hashcode.Rule_start_monitoringDefaultConsequenceInvoker.evaluate(Unknown Source) at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1091) ... 7 more -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.jboss.org/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira