Warning: they are just advices, they are not part of the policy.
Be sure to manage all dependencies by hand in
debian/control. Debian development tools cannot
find them automatically like they do with C programs and libraries
(or like dh_perl does it for Perl, a volunteer to write dh_java
would be welcome).
You can suppress many calls in
debian/rules which are meaningless for Java,
like dh_strip and dh_shlibdeps.
Source package handling is painful, since most Java
upstream programs come with .class files. I
suggest to make a new .orig tarball after
cleaning them, otherwise, dpkg-source will complain.
Java properties files are probably better under
/etc and flagged as configuration files (this
will be integrated in the policy, one day).