After entering the correct credentials we are allowed to access the protected page.
In a typical web application, most pages share certain common areas such as a
navigation menu, a header, footer, and so forth. Since these areas must be identical
across pages, maintaining them can be a tedious process since every change in one
of these areas must be done in each and every page in the application. To avoid this
situation in Java web applications, we can create JSP fragments that can be included
in every page. This way if we need to make a change, we only need to do it in the JSP
In the previous section, we created a login form on both the login.jsp and
loginerror.jsp pages. If we wish to change the look of this login form, we would
have to do it twice, once in each page. This form is a perfect candidate to be extracted
to a JSP fragment.