Thanks Xu and Sebastian for your valuable inputs. But i need this JBPM workflow functionality as one of the feature , along with many others, in my own custom web application. So can this be integrated in my custom application so that the business user can use this as an add-on functionality to create the custom workflow as they wish. The main purpose of the workflow is to create an approval/rejection process for the company's large number of projects. While defining the workflow as per the project the users/actors needs to be selected for the various stages (decided at time of defining the workflow) in the approval/rejection process and they should be able to view/edit/approve/reject/create the project as per the rights given to them by business user at the time of workflow creation, along with the notification and mails as configured while creating the workflow.
Hope I am not rambling and making some sense :)