Firstly, the problem is not in the JSP or JS in your example1. The problem is in what your servlet does when it gets the “…/abcHandler.do?operation=view;” request.
The problem is that you are trying to do stuff that would require a change to the HTTP response headers … after the headers have been sent. That is what the exception / message is saying. (A response is “committed” once the servlet framework starts writing the response. That is typically triggered when something opens the servlet output stream / writer … in preparation to writing the response body.)
To give you a proper diagnosis, and sensible advice on how to fix the specific problem here, we need to see the Servlet / JSP code that is handling the above request.
The “url illegally evaluated to null” message is a bit hard to place. It could be happening before the IllegalStateException
… or after it.
(One possibility is that your JSP code is trying to do something with some ‘url’ attribute that is unexpectedly null
, that is triggering an exception. Then the container’s error handler is trying to set a different response status … and that is failing because the response is already committed.)
In summary, it is not possible to figure out what the root problem is without more information; i.e. the code.
1 – Actually, you are missing a closing quote for the url
initialization … but I assume that’s just a transcription error.