1. from where do we make this request with the query string. do we do this or does the Container do this ?
The container is supposed to support precompilation when the request parameter "jsp_precompile" is used. Check the JSP specification, JSP.11.4.2 Precompilation Protocol. I don't you'll have such a question at the exam.
2. Is there any difference between a jsp which has been declared as a servlet in DD and a jsp which has not been declared as a servlet in DD.
If you declare it in DD, you can access it with different mappings. You can also set some servlet specific properties via the servlet tag.
3. how do we precompile a jsp in tomcat ?
There's a
Tomcat forum. Please ask there, or look at Tomcat's documentation.