Question

A chat application can be implemented using a database (browser send a request conterminously with a particular period and get data from a table which keeps messages).

I want to know that, is there a way to implement a chat application using Ajax and jsp/servlets in HTTP and no database connection ? I know jsp,servlets. How can session,request,responses be handled internally in a jsp/servlet application ?

Answer 1

If you want the non-production, educational version you can use Application Scope:

You can have an application scoped variable holding the chat list

E.g. use <jsp:useBean scope="application"> (one instance per application)

And as long as you have thread safety goggles, and you synchronize where needed, you are fine

But as mentioned, try to check node.js, it seems like the natural candidate for that

Edit:

Note that the application context is per VM, e.g. not the most scaling approach

You can use also ServletContext.setAttribute (same syncronization and scaling issues)