"venkat,s", The Java Ranch has thousands of visitors every week, many with surprisingly similar names. To avoid confusion we have a naming convention, described at http://www.javaranch.com/name.jsp . We require names to have at least two words, separated by a space, and strongly recommend that you use your full real name. Please choose a new name which meets the requirements. Thanks.
In the servlet container software. If you download the source code for one of the many open-source servlet containers (Tomcat, Resin etc.) you can do a search for, for example, "implements HttpServletRequest" to see where it is implemented.