If you read the W3 standards on this you'll find that & is the incorrect and outdated delimiter and ; is the favoured and the correct option. Nice to know Tomcat keeps up with such standards. :)

As a side note, the CGI.pm module has supported both since the first release.

http://www.w3.org/MarkUp/html-spec/html-spec_foot.html -- footnote #26.

- wil