Serial port mouse

Question

back to my expirement:
i try to take signal from serial mouse by the following class but i have a NullPointerException :
   import javax.comm.*;
import java.io.*;
import java.util.*;
public class ComControl implements Runnable, SerialPortEventListener  {
    static CommPortIdentifier portId1;
    static CommPortIdentifier portId2;
    InputStream inputStream;
    OutputStream outputStream;
    SerialPort serialPort1, serialPort2;
    Thread readThread;
    protected String divertCode = "10";
    static String TimeStamp;
public static void main(String[] args) throws UnsupportedCommOperationException {
        try {
          portId1 = CommPortIdentifier.getPortIdentifier("COM1");
          //portId2 = CommPortIdentifier.getPortIdentifier("COM1");
          ComControl reader = new ComControl();
    catch
      (Exception e) {
      TimeStamp = new java.util.Date().toString();
      System.out.println(TimeStamp + ": aaa " + portId1);
     // System.out.println(TimeStamp + ": COM5 " + portId2);
      System.out.println(TimeStamp + ": msg1 - " + e);
public ComControl() {
        try {
            TimeStamp = new java.util.Date().toString();
            serialPort1 = (SerialPort) portId1.open("ComControl", 2000);
            System.out.println(TimeStamp + ": " + portId1.getName() + " opened for scanner input");
           // serialPort2 = (SerialPort) portId2.open("ComControl", 2000);
            //System.out.println(TimeStamp + ": " + portId2.getName() + " opened for diverter output");
        } catch (PortInUseException e) {}
        try {
            inputStream = serialPort1.getInputStream();
        } catch (IOException e) {}
        try {
            serialPort1.addEventListener(this);
        } catch (TooManyListenersException e) {}
        serialPort1.notifyOnDataAvailable(true);
        try {
            serialPort1.setSerialPortParams(9600,
                SerialPort.DATABITS_8,
                SerialPort.STOPBITS_1,
                SerialPort.PARITY_NONE);
            serialPort1.setDTR(false);
            serialPort1.setRTS(false);
          /*  serialPort2.setSerialPortParams(9600,
                SerialPort.DATABITS_7,
                SerialPort.STOPBITS_1,
                SerialPort.PARITY_EVEN);*/
        } catch (UnsupportedCommOperationException e) {}
        readThread = new Thread(this);
        readThread.start();
public void run() {
        try {
            Thread.sleep(100);
        } 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:
            StringBuffer readBuffer = new StringBuffer();
            int c;
            try {
                  System.out.println("aaaaa"+inputStream.read());
                while ((c=inputStream.read()) != 10){
                   if(c!=13)  readBuffer.append((char) c);
                 String scannedInput = readBuffer.toString();
                 TimeStamp = new java.util.Date().toString();
                 System.out.println(TimeStamp + ": scanned input received:" + scannedInput);
                 inputStream.close();
                 if(scannedInput.substring(0,1).equals("F")){
                   outputStream = serialPort1.getOutputStream();
                   outputStream.write(divertCode.getBytes());
                   System.out.println(TimeStamp + ": diverter fired");
                   outputStream.close();
                   } else {
                   System.out.println(TimeStamp + ": diverter not diverted");}
            } catch (IOException e) {}
            break;
}   

Answer 1

Could you post a stacktrace or atleast on which line you are getting this nullpointerexception?