Servlets

Servlets are replacing CGI script at most enterprise computing. They both perform similar operations of creating and displaying HTML pages dynamically. The basic differences between the two:

• CGI - Platform dependent, hence they cannot utilize server's capabilities; spawns new process for every request, hence resource intensive;
• Servlets - Since written in Java they can be executed in servers without any modifications as per "write once, run anywhere"; spawns new threads within the server process, hence lite weight.

Lifecycle of servlets:

• init() - initializes the servlet
• service(ServletRequest , ServletResponse) - all url's access this method and here we delegate to other service methods of form doXXX(HttpServletRequest , HttpServletResponse)
• destroy() - destroys the servlet