i used a coding for getting data from serial port. JOptionbox with "port not found" message is shown when i execute thru jar file. but when i execute thru netbeans, data is received from comm port. why it is happening? i attached the coding i used.

public class SimpleRead implements Runnable, SerialPortEventListener { static CommPortIdentifier portId; static Enumeration portList; InputStream inputStream; SerialPort serialPort; Thread readThread; public static void main(String[] args) { boolean portFound = false; String defaultPort = "COM2";

if (args.length > 0) {
    defaultPort = args[0];
} 

portList = CommPortIdentifier.getPortIdentifiers();

while (portList.hasMoreElements()) {
    portId = (CommPortIdentifier) portList.nextElement();
    if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
    if (portId.getName().equals(defaultPort)) {
        JOptionPane.showMessageDialog("Found port: "+defaultPort);   
        portFound = true;
        SimpleRead reader = new SimpleRead();

    } 
    } 
} 
if (!portFound) {
      JOptionPane.showMessageDialog("port " + defaultPort + " not found."); 
} 

}

private int numBytes;
private String s;



public SimpleRead() {
try {
    serialPort = (SerialPort) portId.open("SimpleReadApp", 2000);
} catch (PortInUseException e) {
System.out.println("port in use");
}

try {
    System.out.println("Getting input Stream");
    inputStream = serialPort.getInputStream();
} catch (IOException e) {
System.out.println(e);
}

try {
    serialPort.addEventListener(this);
} catch (TooManyListenersException e) {
System.out.println(e);
}
serialPort.notifyOnDataAvailable(true);
try {
    serialPort.setSerialPortParams(9600, SerialPort.DATABITS_8, 
                   SerialPort.STOPBITS_1, 
                   SerialPort.PARITY_NONE);
} catch (UnsupportedCommOperationException e) {}

readThread = new Thread(this);
readThread.start();
}



public void run() {
try {
    Thread.sleep(2000);
} catch (InterruptedException e) {}
} 


public void serialEvent(SerialPortEvent event) {
switch (event.getEventType()) {

case SerialPortEvent.BI:

case SerialPortEvent.OE:

case SerialPortEvent.FE:

case SerialPortEvent.PE:

case SerialPortEvent.CD:

case SerialPortEvent.CTS:

case SerialPortEvent.DSR:

case SerialPortEvent.RI:

case SerialPortEvent.OUTPUT_BUFFER_EMPTY:
    break;

case SerialPortEvent.DATA_AVAILABLE:
    byte[] readBuffer = new byte[8];
     byte[] readBuffer2=null;


    try {
    while (inputStream.available() > 0) {
        numBytes = inputStream.read(readBuffer);
        readBuffer2=  new byte[numBytes];
                 for(int i=0;i<numBytes;i++)
                    readBuffer2[i]=readBuffer[i];

    }
    s = new String(readBuffer2);
    System.out.println("readbuffer......"+ s);

    } catch (IOException e) {}
    break;
}
}

}