Servlet

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It is an mini server side program . It is used to create dynamic and protocol
Independent web page . It is loaded and executed on web server .The output of servlet
Is sent to client as response . The output of servlet is static page in MIME format.
The
Security issue which are associated with in a java applet, not applicable for servlet beca-
-use client gets the output of servlet that may be temper by virus .If your web server is
Secured behind firewall then you can say your servlet is also secured.



Working of servlet-:
Servlet is a server side program and it is executed only on the request of client . It is executed only on the request of client .It works behind the web
Server that handles client request-
• client makes a request either using web browser or any other pages.
• Web browser of client send the request as HTTP request as a web server.
• Web server located the requested servlet using web container.
• The servlet engine execute the servlet and generate the MIME response for client.
• The web server deployed servlet into other pages.



How container handles the request-:
• user sends the request to web server.
• Container checks the objects of HTTPServletRequest and HttpServletResponse interfaces.
• The container finds the correct servlet based on the url in the request ,creates a thread for that request ,and passes the request and response objects to the servlet thread.
• The service() method generates the dynamic page and stuffs the page into the response objects .Remember the container still has a reference to the response objects.
• The thread completes ,the container converts the response objects into an http response sends it into backs to the client and then deletes the request objects.