Ever since version 1.1, BufferedServletOutputStream.flush() checks to see if if the response is using an PrintWriter and if it is it ignores the flush request. The question is why? My guess is that it had something to do with the fact that the PrintWriter itself has a buffer because it uses an OutputStreamWriter internally, but that still doesn't make any sense. The net result is that if a servlet author calls flush on the PrintWriter returned from response.getWriter() nothing *appears* to happen. Internally what happens is that the bytes from the PrintWriter's OutputStreamWriter are flushed into the BufferedServletOutputStream's buffer, but they aren't sent to the client. This is not the behaviour that most servlet authors would expect and I don't see any reason in the spec that would mandate it. Does anyone remember or know why BufferedServletOutputStream.flush() does nothing when a PrintWriter is in use? There's bug posted against this behaviour and I don't see any reason why the buffer shouldn't be sent to the client when a PrintWriter is in use, but before I make a change to something that's been around for so long I thought I'd see if anyone remembers why it was done this way to start with.
