[jboss-jira] [JBoss JIRA] (JBRULES-3375) Adding ProcessEventListener throws NPE

Adding ProcessEventListener throws NPE -------------------------------------- Key: JBRULES-3375 URL: https://issues.jboss.org/browse/JBRULES-3375 Project: Drools Issue Type: Bug Security Level: Public(Everyone can see) Reporter: Mario Fusco Assignee: Mario Fusco Description of problem: When you try to add a ProcessEventListener to StatefulKnowledgeSession and you are missing jBPM libraries on classpath, you get a NullPointerException. Version-Release number of selected component (if applicable): BRMS-5.3.0.dev5 Drools-5.3.0.Final How reproducible: Using attached reproducer. Steps to Reproduce: 1. Make sure you don't have any jBPM libs on classpath 2. Create stateful session 3. Add ProcesEventListener (e.g. DebugProcessEventListener) Actual results: java.lang.NullPointerException at org.drools.impl.StatefulKnowledgeSessionImpl.addEventListener(StatefulKnowledgeSessionImpl.java:199) at org.sample.TryProcessListener.main(TryProcessListener.java:20) Expected results: Either meaningful exception (like NojBPMException) or correct addition of listener Additional info: It only affects StatefulKnowledgeSession, the StatefulKnowledgeSession runs just fine.