Thnaks for the reply bruce.I did as per your suggestion.I have set the ResponseFormat for the WebGet attribute on the Operational Attributes as json.After that i deploy the webservice and checked-it in SoapUi and fiddler.I am not getting any difference in the response.Can you please suggest how can i check whethere the encoding data is of JSON type.
I know i am asking very silly questions 
, but please help me on this.,
Regards
Subrat