jBPM - How to trace a lifecycle of a process

Just need to add a ProcesEventListener() to the ksession.

KnowledgeBase kbase = readKnowledgeBase();
StatefulKnowledgeSession ksession = kbase.newStatefulKnowledgeSession();

CustomProcessEventListener customProcessEventListener = new CustomProcessEventListener();
ksession.addEventListener(customProcessEventListener);
...
...

ksession.startProcess("com.sample.MyTaskFlow", params);

And here is the sample CustomProcessEventListener();

private static class CustomProcessEventListener implements ProcessEventListener {

 @Override
 public void afterNodeLeft(ProcessNodeLeftEvent arg0) {
  // TODO Auto-generated method stub
  
 }

 @Override
 public void afterNodeTriggered(ProcessNodeTriggeredEvent arg0) {
  // TODO Auto-generated method stub
 }

 @Override
 public void afterProcessCompleted(ProcessCompletedEvent arg0) {
  // TODO Auto-generated method stub
  logger.debug("Process has completed.");
  System.exit(0);
 }

 @Override
 public void afterProcessStarted(ProcessStartedEvent arg0) {
  // TODO Auto-generated method stub
 }

 @Override
 public void afterVariableChanged(ProcessVariableChangedEvent arg0) {
  // TODO Auto-generated method stub
   
  }

 @Override
 public void beforeNodeLeft(ProcessNodeLeftEvent arg0) {
  // TODO Auto-generated method stub
   
 }

 @Override
 public void beforeNodeTriggered(ProcessNodeTriggeredEvent arg0) {
  // TODO Auto-generated method stub
   
 }

 @Override
 public void beforeProcessCompleted(ProcessCompletedEvent arg0) {
  // TODO Auto-generated method stub
  logger.debug("Process is going to be completed.");
 }

 @Override
 public void beforeProcessStarted(ProcessStartedEvent arg0) {
  // TODO Auto-generated method stub
  
 }

 @Override
 public void beforeVariableChanged(ProcessVariableChangedEvent arg0) {
  // TODO Auto-generated method stub
  
 }
 
}

As you can see, you can do many things on every stage of a process.