Tech Mentro

This post demonstrate the use of external objects in JSP. In this example, objects of a user defined class are created & shared among requests with the help

Inter application forwarding the facility of forwarding request from on application to another on the same server. inter application forwarding is facilitated

To read initialization parameters from ServletContext, getInitParameter() method is used. this method is defined in both ServletContext & ServletConfig.

Request redirection is the facility of redirecting the browser to another server application by providing a url as the response of current request.

In the practical example of inter application forwarding, we will create App1 and App2 applications which we have discussed in the last post.

Can destroy() method be invoked explicitly? This is the most frequently asked interview question of java. Most of the people give wrong answer of it.

Can more than one servlet objects be created in a web application? This is the most frequently asked question in interviews. The correct answer is yes.

What is the need of creating servlet objects at the time of deployment? If need is understood we can find out how we can as the server to create mulitple servlet

Reading multi valued parameters in a servlet is required when input form contains multi valued input controls such as check boxes and combo boxes.

Reading unknown parameters in a servlet, is required when the servlet programmer doesn't know how many parameters are sent by the user as part of request.

In this file uploading example of servlet we have used apache commons file upload API for processing multi part request.

File downloading is a two step process. In the first step, links of the files are obtained and in the second step, files are downloaded using the links.

A cookie is a token which is sent by the server as part of the response and is returned back by the client as part of the subsequent requests.

This post contains a practical example of state management using cookie. In it user name is maintained between two requests with the help of a cookie.

URL rewriting is another browser independent approach of maintaining the client's state between requests. In URL rewriting, state is dynamically appended to

hidden form field provide and alternative way of state management which is browser independent i.e. hidden form field can't be disabled from the browser.

HttpSession is a Servlet API interface. Implementation of it is provided by server vendors. An object of type HttpSession can be get created for each user.