Hi S Das,
For 1 year old update you may check my posts regarding executable bpmn on Bruce Silver blog. To summarize, I am very pessimistic about the idea of executable bpmn as a whole. If you have no time to follow the links below, here is one line summary:
A lot of time spent to produce hardly manageable code
And I would better avoid engaging into discussion about specific implementations, as my comments may be even more acid...
http://www.brsilver.com/2011/11/07/executable-bpmn-2-0/#comments
http://www.brsilver.com/2011/11/14/more-on-executable-bpmn-2-0/
Hope this helps,
Alex