Actuator code in the Raspberry Pi (stripped down version)

gistfile1.txt

public class Receiver{
    final GpioController gpio;
    final GpioPinDigitalOutput pin;
    {
        gpio = GpioFactory.getInstance();
        pin = gpio.provisionDigitalOutputPin(RaspiPin.GPIO_00, "Relay");
    }
    
    public void run(String message){
        System.out.println("Message received "+message);
        if(message.equals("ON")){
           pin.high();
        }else if(message.equals("OFF")){
            pin.low();
        }
    }
}