I've tried posting this question twice to the Tomcat developpers. There's even a bug open. So far nobody has even commented on my suggestion to add a parameter to not pass the encoding to jikes. It seems that none of the developpers of Tomcat are using their container to write web application on windows otherwise the time it takes to recompile would've driven them nuts. Looks like the only option is for somebody to patch it and send the patch to the guys working on Jasper.