What is a Servlet? A Java program that operates in conjunction with a Web server, and can output Hypertext Markup Language (HTML) to a browser or even communicate with Java applets. Servlets offer an alternative to using Common Gateway Interface (CGI) and server application programming interfaces (SAPIs) to communicate with Web server processes. What is a Servlet Container? A Servlet Container is a program which can receive requests from web pages and redirect those requests to a Servlet object.Normal Java application’s starting point is Main( public static void main(String args[] )) method. When ever java application needs to start, main method of the application should be invoked. But in case of Servlet this is not true, Servlet doesn’t contain any main method. So who will initiate and run the method of Servlet. It’s Container who has the full control of Servlets. It is container which is responsible to manage the life-cycle of servlet. Web server hands the request to