A couple of RFC's?:
1. GZIPFilter.doFilter doesn't pass non-http requests down the chain, effectively killing them? Surely that's a bug!
2. CacheFilter.doFilter doesn't instanceof HttpServletRequest (or res), it just casts req. Surely that'd throw a ClassCastException for any non-http request.
And a wish: I'd expect to find both these filters (premade and super-thoroughly tested) in an enterprise server, so all gumbies like me have to do is configure them via the console.
And a wee whinge: No source code in the jar. You inveterate putz!