devendra katiyar [http://community.jboss.org/people/dev.katiyar] created the discussion "Event Listener Problem" To view the discussion, visit: http://community.jboss.org/message/569802#569802 -------------------------------------------------------------- I am implement Log Event Listener using example given in user guide <process name="EventListener" xmlns="http://jbpm.org/4.4/jpdl">   <on event="start">     <event-listener class="org.jbpm.examples.eventlistener.LogListener">       <field name="msg"><string value="start on process definition"/></field>     </event-listener>   </on>   <start>     <transition to="wait"/>   </start>   <state name="wait">     <on event="start">       <event-listener class="org.jbpm.examples.eventlistener.LogListener">         <field name="msg"><string value="start on activity wait"/></field>       </event-listener>     </on>     <on event="end">       <event-listener class="org.jbpm.examples.eventlistener.LogListener">         <field name="msg"><string value="end on activity wait"/></field>       </event-listener>     </on>     <transition to="park">       <event-listener class="org.jbpm.examples.eventlistener.LogListener">         <field name="msg"><string value="take transition"/></field>       </event-listener>     </transition>   </state>   <state name="park"/> </process> and LogListener class like below public class *LogListener* implements EventListener {   // value gets injected from process definition   String msg;   public void notify(EventListenerExecution execution) {     List<String> logs = (List<String>) execution.getVariable("logs");     if (logs==null) {       logs = new ArrayList<String>();       execution.setVariable("logs", logs);     }     logs.add(msg);     execution.setVariable("logs", logs);   } } but when I am testing using Junit ProcessInstance processInstance = executionService.startProcessInstanceByKey("EventListener"); In above line getting Nullpointer Exception? can any one help regards this , or any other reference to implement Event Listener in jbpm4 Thanks all -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/569802#569802] Start a new discussion in jBPM at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]