async per servlet 3.0

[Mete BALCI]

Hello,

I am trying to use Servlet 3 async support in Tomcat 7.0.21. I tried setting
annotation asyncSupported=true and writing this to web.xml, tried using apr
and nio, still getting false from isAsyncSupported, what am I missing ?

Mete

PS: There is no filter, just a single servlet overriding doPost, marked
with @WebServlet(asyncSupported = true, urlPatterns = {"/2/*"})