import jssc.SerialPort;
import jssc.SerialPortException;
import java.nio.charset.StandardCharsets;
import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;

import java.util.Arrays;

import static java.nio.charset.StandardCharsets.US_ASCII;

public class Main {

    public static void main(String[] args) {
        SerialPort serialPort = new SerialPort("/dev/cu.usbmodem1411");
        try {
            serialPort.openPort();//Open serial port
            serialPort.setParams(9600, 8, 1, 0);//Set params.

            while (true) {
                byte[] buffer = serialPort.readBytes(100);
                System.out.print(new String(buffer, US_ASCII));

            }

        } catch (SerialPortException ex) {
            System.out.println(ex);
        }

    }
}