Java developers

I am getting an error 500: ERROR: Cannot forward. The resource "/ssd/main/error.jsp" has already committed the response.

What exactly does this mean and how can I fix it?

Here is part of my code:

sendPage("/ssd/main/error.jsp", request, response);

Then I have a method:
protected void sendPage(String url, HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

RequestDispatcher dispatcher =
getServletContext().getRequestDispatcher(url);
dispatcher.forward(request, response);
}

Any help is greatly appreciated

Quick scenario. I have a class method that runs bat files. In the bat file, is a call to the java compiler. If the bat file (and therefore the internal commands) runs successfully it indicates success and dumps the screen response into a StringBuffer.

If it fails, it indicates that it failed and does the same thing.

I can get it to run successfully, so I know the success message works just fine. When I intentionally tried to break it (ie., changed the name of the file to be compiled to something that is nonexistant) to test the failure message, instead of returning a failure message, it hung - I even let it run all night (had to go to bed anyway).

Is there a way to poll to see if the process is hung and then cancel it?

Thanks in advance.

OK, I work at a company doing J2EE and bug reports here, like most places, are vague and uninterprettable. Hence:

Title: Some problems occured when we had acces (sic) to web
Desc: Everyone experiences this error from time to time trying to access the web sites.
Priority: High

how do I go about adding a GUI to a text-based memory game that I've written? I made a new class called GUI and extended a JFrame but I don't know where to go from there...

any help is greatly appreciated.