// Add an event listener
serialPort.addEventListener(new SerialPortEventListener() {
@Override
public void serialEvent(SerialPortEvent event) {
if (event.isRXCHAR()) { // If data is available
try {
// Read the data
byte[] data = serialPort.readBytes();
System.out.print(new String(data));
} catch (SerialPortException ex) {
System.out.println("Error reading data: " + ex);
}
}
}
});

} catch (SerialPortException ex) {
System.out.println("Error opening port: " + ex);
}
}
}

import jssc.SerialPort;
import jssc.SerialPortException;
import jssc.SerialPortEvent;
import jssc.SerialPortEventListener;

public class SimpleRead {
public static void main(String[] args) {
String portName = "COM1"; // Replace with your COM port
SerialPort serialPort = new SerialPort(portName);

try {
// Open the port
serialPort.openPort();

// Set the parameters
serialPort.setParams(SerialPort.BAUDRATE_9600,
SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);