IllegalStateException what are the practical causes.....

[Gabriel Fox]

Hello, i got this exception after running a query and populating JSP with result of query. The same screen works OK before. Are there practical/exact causes of this exception and definite ways of guiding against them. Because i am not flushing the output stream as far as i know.
All ideas are welcomed..........
java.lang.IllegalStateException: Response has already been committed
at com.evermind[Oracle9iAS (1.0.2.2.1) Containers for J2EE].server.http.EvermindHttpServletResponse.sendError(EvermindHttpServletResponse.java:1067)
at com.evermind[Oracle9iAS (1.0.2.2.1) Containers for J2EE].server.http.EvermindHttpServletResponse.sendError(EvermindHttpServletResponse.java:1261)
at com.evermind[Oracle9iAS (1.0.2.2.1) Containers for J2EE].server.http.HttpApplication.serviceJSP(HttpApplication.java:5428)

[Bear Bibeault]

Gabriel, this error usually occurs when you attempt to perform a forward or redirect after some output has beem sent to the response. First thing to do is to check that you are deciding to redirect or forward before you attempt any output.
hth,
bear