Our build process already includes the application's dependencies inside the jar, and packages it into an installable deb file that places the app, its config, and the init file in the right locations.

I have a database and a cache server. They don't run on the same server as the application jar... they run on separate machines tuned to their purpose. Why would I want them packaged together? So my team doesn't have to run "apt-get install postgresql" on their dev machines? Or to maintain an exactly consistent dev environment?