Use this code to explicitly send an exception to the JSP error page from a servlet:

public void doPost(HttpServletRequest request, HttpServletResponseresponse)      throws  ServletException, IOException {	...	//Create your exception	Exception myException = new Exception    ("error message");	//Set this request attribute	request.setAttribute("javax.servlet.jsp.jspException", myException );	//forward to the error page                RequestDispatcher rd =request.getRequestDispatcher("/Error.jsp");	rd.forward(request, response);}

The JSP error page simply accesses the implicit object exception to extract the error message.