The Derby downloads page (http://incubator.apache.org/derby/derby_downloads.html) says to get http://cvs.apache.org/builds/jakarta-servletapi-4/nightly/ . But clicking on the 'src' directory at that URL just gives you a link back to the parent directory.
http://www.ibiblio.org/maven/servletapi/jars/
or
http://www.ibiblio.org/maven/geronimo-spec/jars/
-- Jeremy
