First of Thanks Demian for your quick reply.
The example helped me too much but the test case given for EscalationProcessTest.java fails while claiming the task with the follwing error:
org.jbpm.task.service.PermissionDeniedException: User '[User:'Steve Rogers']' was unable to execution operation 'Claim' on task id 1 due to a no 'current status' match.
Please give a look on it.
Regards,
Hardik Dave.