How to handle Exception in jBPM5 ?

Issue

• How can we catch any exception/error/fault in jBPM5, should some code within a script fail? Currently, if code fails we have no way of knowing other than the engine seemingly stops executing the workflow.
• We are using jBPM5.4 and we are trying to handle an exception thrown from a service task using boundary Error Intermediate Event. But, even after the exception occurs in Service Task the exception handling is not taking place as expected. Can you please advice us how to achieve it in jBPM5.4 ? We are aware of the fact that jBPM5.4 is not supported in JBoss Enterprise BRMS 5.3.x .