When I tried for first time to acheive this, It didn't work. Even meta-tags inside head tag didn't work.
Finally this worked after few permutations... The trick is to add these lines even before HTML tag. I guess that these headers are respected by browsers when they see it before HTML content.
This works for sure... If anybody knows more cleaner solution, please do let me know...
Sources: You can find this information any JSP book. I dont remember where I got the tip to Adding these before html tag.