Read from serial and print

ArduinoJava.java

package arduinojava;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStream;
import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import gnu.io.SerialPortEventListener;
import java.util.Enumeration;

/**
 *
 * @author Toshiba
 */
public class ArduinoJava implements SerialPortEventListener {

    private static String s;

    public String GetS() {
        return s;
    }

    public void ReSetS() {
        s = "-";
    }

    SerialPort serialPort;
    /**
     * The port we're normally going to use.
     */
    private static final String PORT_NAMES[] = {
        "COM19", // Windows
    };

    /**
     * A BufferedReader which will be fed by a InputStreamReader converting the
     * bytes into characters making the displayed results codepage independent
     */
    private BufferedReader input;
    /**
     * The output stream to the port
     */
    private OutputStream output;
    /**
     * Milliseconds to block while waiting for port open
     */
    private static final int TIME_OUT = 2000;
    /**
     * Default bits per second for COM port.
     */
    private static final int DATA_RATE = 2400;

    public void initialize() {
        // the next line is for Raspberry Pi and 
        // gets us into the while loop and was suggested here was suggested http://www.raspberrypi.org/phpBB3/viewtopic.php?f=81&t=32186
        //  System.setProperty("gnu.io.rxtx.SerialPorts", "/dev/ttyACM0");

        CommPortIdentifier portId = null;
        Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();

        //First, Find an instance of serial port as set in PORT_NAMES.
        while (portEnum.hasMoreElements()) {
            CommPortIdentifier currPortId = (CommPortIdentifier) portEnum.nextElement();
            for (String portName : PORT_NAMES) {
                if (currPortId.getName().equals(portName)) {
                    portId = currPortId;
                    break;
                }
            }
        }
        if (portId == null) {
            System.out.println("Could not find COM port.");
            return;
        }

        try {
            // open serial port, and use class name for the appName.
            serialPort = (SerialPort) portId.open(this.getClass().getName(),
                    TIME_OUT);

            // set port parameters
            serialPort.setSerialPortParams(DATA_RATE,
                    SerialPort.DATABITS_8,
                    SerialPort.STOPBITS_1,
                    SerialPort.PARITY_NONE);

            // open the streams
            input = new BufferedReader(new InputStreamReader(serialPort.getInputStream()));
            output = serialPort.getOutputStream();

            // add event listeners
            serialPort.addEventListener(this);
            serialPort.notifyOnDataAvailable(true);
        } catch (Exception e) {
            System.err.println(e.toString());
        }
    }

    /**
     * This should be called when you stop using the port. This will prevent
     * port locking on platforms like Linux.
     */
    public synchronized void close() {
        if (serialPort != null) {
            serialPort.removeEventListener();
            serialPort.close();
        }
    }

    /**
     * Handle an event on the serial port. Read the data and print it.
     */
    public synchronized void serialEvent(SerialPortEvent oEvent) {
        if (oEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
            try {
                if (input.ready()) {

                    String inputLine = input.readLine(); //HERE
                    s = inputLine;
                    System.out.println(inputLine);
                }

            } catch (Exception e) {
                System.err.println(e.toString());
            }
        }

        // Ignore all the other eventTypes, but you should consider the other ones.
    }

    public static void main(String[] args) throws Exception {

        Thread t = new Thread() {
            ArduinoJava main = new ArduinoJava();

            public void run() {
                main.initialize();

                while (true) {
                    try {

                        if (!main.GetS().equals("-")) {
                            System.out.println("S :" + main.GetS());
                            main.ReSetS();
                        }
                        Thread.sleep(50); // keep this mess open for 1000 sec 
                    } catch (InterruptedException ie) {
                    }
                }

            }
        };

        t.start();

    }
}