Sunil,
What Sriram is trying to say is that you need to give your filter expression's key value also as a string character, not just the filter expression itself as string.
For that all you need to do is escape the quotes and pass your value. That is,
setFilterExpr("[dept] = \"CSEE\" ");
OR
setFilterExpr("[dept] = 'CSEE' ");
One of these should work.
Regards,
Rutika Bodas