1. Diozero
Java Device I/O library that is portable across Single Board Computers. Tested with Raspberry Pi, Odroid C2, BeagleBone Black, Next Thing CHIP, Asus Tinker Board and Arduinos. Supports GPIO, I2C, SPI as well as Serial communication. Also known to work with Udoo Quad.
2. pigpioj
Java JNI wrapper around the pigpio C library
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