The Pi4J library is developed by Robert Savage and is used to interact with the GPIO pins. Communication with the GPIO pins is not done by pure Java but uses a native library developed by Gordon Henderson. This library is bundled within the Pi4J library and is used automatically. The Pi4J project consists of multiple libraries which are as follows:
- pi4j-core.jar: Always needed, and includes the pi4j native library
- pi4j-device: Wrappers used for interactions with different kind of peripheral and different Raspberry Pi expansion boards
- pi4j-gpio-extension.jar: Used by pi4j-device.jar or for custom extension implementations
- Pi4j-service.jar: Provides listeners for GPIO pins
We will always include all libraries so we are sure to have all the dependencies and will make it easier for you to extend the projects without the need to search for the corresponding libraries of the same version being used...