JEE

What are the different variable scopes available?
Page, Request, Session, Ap
What is the difference between GenericServlet and HttpServlet?
GenericServlet supports any protocol. HttpServlet supports only HTTP protocol. By
extending GenericServlet we can write a Servlet that supports our own custom protocol
or any other protocol
How can I implement a thread-safe JSP page
You can make your JSPs thread-safe adding the directive <%@ page isThreadSafe="false" % > within your JSP page