JSP Request forwarding

If there is some arbitrary JSP, say x.jsp, then I rename it to _x.jsp, and then write my own x.jsp which has '<jsp:forward page="_x.jsp"/>', what could possibly appear different to _x.jsp ?
i.e. Is there anything that anyone can think of that doesn't cause this request forwarding to appear transparent to the original JSP ?

Problem resolved.
I didn't think there would be a reason

Thanks.