Debian package examples for Java software

I'm looking for good examples of how Java software is packaged on the
Debian family of operating systems. Ideally, very simple examples with
just a JAR file and a few configuration files. Where can I find such
projects, e.g. on Salsa?

To extend on that, I try to find out how - if at all - (Java) software
can be packaged as a Debian package, so that it can be installed
root-less, i.e. with an unprivileged user. Where can I find
information about that?

Thank you for your help,
Peter