Null pointers are most of the time caused by an object not being there (ie empty). Some remarks: a bit strange that an anonymous user has the administration role. Normally you would have a real user doing this kind of stuff. And have you checked that rupesh does indeed has access rights to the database?
Regards,
Ronald
Are you sure the HttpResponse the return object of your query? You need to provide an entity which matches all the colums you retrieve exactly. Usually it's also best to explicitly state which columns you want to retrieve, and provide and alias which matches your attribute names exactly.
So write your queries as follows:
select c1 as "col1”, c2 as “col2” from mytable