If you just read the early draft specification for Servlet 3.0 or JSR-315, then you might not be aware of some other changes that have made their way into the spec. This post by Rajiv Mordani discusses the changes made to the Servlet 3.0 specification since its early draft version which include: Ease of Development, Pluggability and Asynchronous processing Read Rajiv's post 'Servlet 3.0 - from the source' http://weblogs.java.net/blog/mode/archive/2008/12/servlet_30_from.html