Question

when I write a <jsp:useBean>, the class attribute determines
the class of the new object (if one is created). it also determines
the type of the reference variable used in the generated servlet.

In JSP:

<jsp:useBean id="person" class="foo.Person" scope="page" />

Generated servlet:

 food.person = null;
 if(person==null) person = new foo.Person();

Is there a way to change the reference type from the actual
object type? In other words, make the reference type to be Person, and the object type to be say, Student.

Answer 1

No, it’s not possible.

But in a properly designed application, the controller (a servlet, or an action of your preferred MVC framework) creates the bean, and the view uses it.

And <jsp:useBean> is obsolete for years. Use the JSP EL.

Controller:

request.setAttribute("person", new Student());

View:

${person.id} - <c:out value="${person.name}"/>