LED Strips
WS2811B / WS2812B / Adafruit NeoPixel
Provides support for WS2811B / WS2812B aka Adafriut NeoPixel LEDs via a JNI wrapper around the rpi_ws281x C library as well as a native Java implementation that uses SPI. Also controls APA102 LED strips using SPI.
Colour Coding
All colours are represented as 24bit RGB values.
The README on jgarff’s GitHub project provides some good tips for if you are having issues controlling LED strips, in particular the SPI section.