Well, Servlets new specifications 3.0 has be pondered.
The new 3.0 specs changes the servlet technology up-side down the way that EJB3.0 did.
In the new release servlets makes heavy use of annotations to obsolete XML meta data (hell) and to make all its objects as POJOs .
Many changes have added to the new specs such request suspension and allowing servlets to be added to the web app after deployment that all were not allowed in the previous release that held the number 2.4.
you can find more in this interesting article :