Is this really still a complaint in 2016? Your phone has that much RAM.
Honestly if you're worried about Java heap size, spin up a t2.medium instead of a t2.small for your build pipeline. Running Jenkins on a Raspberry Pi is probably not a great idea if you're writing any serious application.
The JVM adds something like 400MB to every layer of a docker container resulting in multi gigabyte containers. Additionally the memory requirements for running a JVM put you immediately into the t2.medium range which will cost you 4X cost over a t2.nano for simply choosing to run Java instead of something with a smaller runtime footprint.
Don't run production code on a nano.
Don't run production code on a nano.
I don't care what language you're using, if you find yourself saying "well, I could run on a nano" just stop.
Perhaps this is the "writing on the wall" that containers aren't what you should be using to deploy your app.
Just because it's the "latest craze" doesn't mean it's the best solution for the task at hand.