The new behavior introduced in: https://bz.apache.org/bugzilla/show_bug.cgi?id=56917 Can cause strange and mysterious errors. For example, passing an invalid value fo sendRedirect(): response.sendRedirect("SomePage.html?value=Some Word") will now generate a 404 error indicating that the page containing the sendRedirect() call is not found. In this case the real error is that the parameter is not URI encoded. Additionally, because of the manner it's called, no diagnostic page is generated. The developer is left scratching their head wonder what went wrong. It would be very helpful if the IllegalArgumentException that get's caught in o.a.c.c.Response at line 1412 could be logged.
Fixed in trunk for 9.0.0.M3 onwards, 8.0.x for 8.0.32 onwards and 7.0.x for 7.0.68 onwards.