init-param and context-param

Question

What is the difference between and !?

Answer 1

and are static parameters which are stored in web.xml file. If you have any data which doesn't change frequently you can store it in one of them.

If you want to store particular data which is confined to a particular servlet scope, then you can use .Anything you declare inside is only accessible only for that particular servlet.The init-param is declared inside the tag.

     HelloWorldServlet
     HelloWorldServlet
     
         Greetings
         Hello
     

and you can access those parameters in the servlet as follows:

out.println(getInitParameter("Greetings"));

If you want to store data which is common for whole application and if it doesn't change frequently you can use instead of servletContext.setAttribute() method of the application context. For more information regarding usage of VS ServletContext.setAttribute() have a look at this question. context-param are declared under the tag web-app. You can declare and access the as follows

    
        Country
        India
    
    
        Age
        24
    

Usage in the application either in a JSP or Servlet

getServletContext().getInitParameter("Country");
getServletContext().getInitParameter("Age");