Java.lang.IllegalStateException: Cannot forward ...

Question

as OutputStream or Writer has already been obtained.
Getting this error. Using
Jdk1.3.1_01 with Tomcat. This did NOT happen in JavaWebServer2.0 (30 day demo version).
This is the part of the code that is giving me the problems.
RequestDispatcher showDispatcher = getServletContext().getRequestDispatcher(showService);
showDispatcher.forward(req,res);
What I am doing is using this as a central servlet that all jsp pages must go through to get to a servlet, which in turn returns to a jsp page.
Now I will note this, as i've seen before in other similar requests. I am NOT using any Printwriters in this servlet.
The "showService" is a hidden field on the request jsp page that tells this servlet where to go afterwards.
As I said before, this worked with NO problems at all. Considering I wanted to get away from JWS2, and go to Tomcat, this is the problem it gave me. I have been able to get all JSP pages to work. Servlets all go through this, so i didn't want to change all my servlets and jsp pages to go direct to the servlets. (Security thing).
Thanks to anyone who can help me out.
...Ordio

Answer 1

taskDispatcher.include(req, res);
showDispatcher.forward(req,res);you can use include and forward at the
same time in the old Servlet/JSP version, as the
include function will automatically flush the
output(say the JSP) to the client, that's why
something's written out but you don't know! while,
apparently, forword function requires nothing shoud be
sent to client.Makes sense to me. :)
since the program works fine in Jave web server, i bet
you must be using Tomcat 3.X or even older which use
old version of Servlet/JSP specs and implementations.Ahh... that may explain why. I am using tomcat 3.2.3.
So, either update the Tomcat to 4.0(which is yet a
beta version), or find any other server else. (I
assume you don't want to re-write the whole program).Yeah, you are right... I do not want to re-write everything to get it to work. I will update to Tomcat 4 (I know it is in beta, and supposedly it was supposed to be released today.)
Yeah, i just grabbed tomcat 4, and here's the info from the Release Plan 4.0
Sunday, September 9, 2001 Tomcat 4.0 Release Candidate 1
Thursday, September 13, 2001 Tomcat 4.0 Release Candidate 2
Monday, September 17, 2001 Tomcat 4.0 Final Release
Thanks for helping me out, and letting me know that the problem is likely tomcat 3.X... I will try this out on 4, and reply later.
...Ordio