Can you use the "errorPage" functionality in the same page as a <jsp:include>? When an exception occurs, the JSP tries to forward to the "errorPage." The problem is that you cannot forward after the buffer has been flushed and including annother resource flushes the buffer (setting the "autoFlush" page attribute has no effect.) So, are the "ErrorPage" exception handling and the <jsp:include> mutually exclusive?
Yes they are effectively mutually exclusive in the JSP 1.1 spec. Fortunately, the JSP 1.2 spec is in public draft right now and supports flush="false" for <jsp:include>.