Premature socket disconnect with Tomcat

Question

I'm seeing an intermittent problem with Java servlets, which I'm having real trouble tracking down... I wonder if anyone has seen something similar?
I am POSTing a request to the servlet, with about 1Kb of data in the request. The servlet sends a response by calling sendRedirect(new URL). In some circumstances, however, tomcat appears to be aborting the TCP connection prematurely... causing the browser (IE6.0) to first resubmit the POST request, and then give up and say "The page cannot be displayed".
The frequency of occurance seems to vary according to the network latency and the content length of the POST request. I also tried setting tomcat 3.3.1a's "socketCloseDelay" parameter on the Http10Connector - which does make the problem occur less, but doesn't make it go away completely. Using Coyote didn't help, either.
I suspect that there's something wrong with my code! But I'm not sure how to track it down. I wonder if there is something that I should be flushing, perhaps?
Any ideas very much appreciated!!
Thanks
Charlie

Answer 1

Aha! I've discovered my problem (see previous post). Don't do this...
public void doPost(HttpServletRequest aRequest,
HttpServletResponse aResponse)
PrintWriter lOutStream=aResponse.getWriter();
aResponse.sendRedirect(some URL);
It'll work most of the time, but if you get a request with about 1Kb of data, and a network latency of about 40ms, it'll confuse IE6.0 by untidily closing the TCP connection. Obviously.
The answer, of course, is only to call getWriter if you're genuinely intending to write to it (in which case, you won't be allowed to call sendRedirect).
I'll try and raise a bug somewhere.
Charlie