I have gone through below links so far-:
Page scope- scope in jsp
What are the different scopes in JSP?
difference between page and request
I want to know about what are the differences between page scope and request scope? If I consider use of RequestDispatcher.forward() & HttpServletResponse.sendRedirect() to same or different page, then how these scopes will work?
If request is forwarded to same page then how these two scopes will differ?
Page scope is a scope that's only valid while processing one single JSP. Typically, if one JSP forwards to itself, the second instantiation will share the original request scope but will receive a brand new page scope. This can make sense if you include 2 instances of the same fragment in on page: all will share the request scope with the caller, but each instance will use its own page scope.
sendRedirect is quite a different thing! Redirecting is returning to the client a special response containing the new URL to fetch in its headers. But that also means that the redirect will use a different HTTP request and as such will have a different request scope. Said differently only session scope is shared between redirected pages - and only when you redirect to the same web application.