I'm using dronekit with SITL/3DR solo for a minimalistic prototype.
At one point I would like to move some of the ground control station code (written in Java/Scala) to the companion computer for better real-time handling. Only to find that Java is not included in its shipped Yocto linux (I can't find it in repository either).
Is there an easy way to install java on the companion computer?
Not really, installing and running the Java version of the Dronekit API is not supported at the moment, so there's no available instructions on how to proceed. Though installing Java should be as simple as running the Oracle Java installer for arm: http://www.oracle.com/technetwork/java/javase/downloads/jdk7-arm-downloads-2187468.html