Use jars from Debian?

On IRC I had a discussion about our jar issues with @dpocock. He had a GSoC-Student solving this problem for debian, so if we trust them, we can get the jars from their. Log attached.

20:11 < pocock> krt: you mean that if 3 apps have copies of libphonenumber in their repo, you will build it 3 times?  Or you just build one copy of libphonenumber and keep it somewhere else?
20:15 < krt> we build it everytime right now.
20:17 < pocock> krt: I had a GSoC student working on verified source builds of Maven projects during the summer
20:17 < pocock> the goal of that project was to get library JARs into Debian
20:18 < pocock> if there is anything I can do to help create a pool of libraries built from source then please let me know
20:20 < krt> pocock: You should talk to CiaranG if he is available, he had some ideas on getting rid of the jar-madness. my approach would have been 
             to include buildscripts for every jar/revision encountered and add them to mavenlocal
20:20 < pocock> personally, I feel you would be duplicating what we already do in Debian
20:21 < pocock> nothing gets into Debian without at least two developers checking that it is 100% built from source
20:21 < krt> if there is work already been done, i'd prefer this rather than deploying our own thing
20:22 < pocock> you can see some of the JARs I sponsored for Debian here: https://qa.debian.org/developer.php?login=daniel@pocock.pro
20:22 < pocock> you could probably create some script that fetches them from Debian mirrors and extracts the JARs
20:23 < krt> or just add them to our buildserver setup, we currently use debian, but i don't know how portable we are/want to be
20:24 < deki> i like the idea of using jars from debian
20:24 < pocock> actually installing the JARs as packages with dpkg could be troublesome because the newest JARs are not always in backports
20:24 < pocock> for F-Droid, I would suggest grabbing JARs from sid and keeping a copy of every version that appears
20:25 < pocock> for as long as you need it