...The jinput project currently lives here:
https://jinput.github.io/jinput/
Communication with the Steam Controller happens via the (low level) Java wrapper for libusb, found here:
http://usb4java.org/quickstart/libusb.html
This project is written for Java 1.6 or greater. It is tested to work on Windows and Linux, but on Linux custom udev rules are required, e.g.
https://wiki.gentoo.org/wiki/Steam_Controller#Manual_udev