Dot matrix printer problem (/dev/parport)

Dear experts:

I have a problem with a dot matrix printer. Im in a Linux/Java App project thats prints tickets to it.
But i cant print on it. I dont know why. On Windows it works fine, but the javax.comm for windows is obviously different.
Can anyone help me?

Heres a log of what happens...


Starting printing test...
On Printer 3 :/dev/parport0
SerialDriver(port) Method
DefaultPort: /dev/parport0
Open Method
Trying to open port with Javax...
Opened the port Successfully with Javax!!
Obtaining the OutputStream...
OutputStream OK
Linux: /dev/parport0 opened succesfully
Creating StringBuffer...
Appending text
    +------------------------------+
    |          Tienda PRO          |
   +------------------------------+

        Print Test Successful













Converting to Bytes while replacing nulls
[B@dc024a
Opening FileOutputStream
Writing to printer
Couldnt send data to port due to :

java.io.IOException: Invalid argument
      at java.io.FileOutputStream.writeBytes(Native Method)
      at java.io.FileOutputStream.write(FileOutputStream.java:247)
      at com.storecheck.detailconnect.utils.TicketPrinter.printLPT(TicketPrinter.java:362)
      at com.storecheck.detailconnect.ui.panels.SettingsPanel.btnProbarActionPerformed(SettingsPanel.java:1447)
      at com.storecheck.detailconnect.ui.panels.SettingsPanel.access$3100(SettingsPanel.java:45)
      at com.storecheck.detailconnect.ui.panels.SettingsPanel$19.actionPerformed(SettingsPanel.java:854)
      at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1849)
      at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2169)
      at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)
      at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)
      at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:234)
      at java.awt.Component.processMouseEvent(Component.java:5488)
      at javax.swing.JComponent.processMouseEvent(JComponent.java:3093)
      at java.awt.Component.processEvent(Component.java:5253)
      at java.awt.Container.processEvent(Container.java:1966)
      at java.awt.Component.dispatchEventImpl(Component.java:3955)
      at java.awt.Container.dispatchEventImpl(Container.java:2024)
      at java.awt.Component.dispatchEvent(Component.java:3803)
      at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4212)
      at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3892)
      at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3822)
      at java.awt.Container.dispatchEventImpl(Container.java:2010)
      at java.awt.Window.dispatchEventImpl(Window.java:1774)
      at java.awt.Component.dispatchEvent(Component.java:3803)
      at java.awt.EventQueue.dispatchEvent(EventQueue.java:463)
      at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:242)
      at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:163)
      at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:157)
      at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:149)
      at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)

Closing outputStream...
outputStream Closed Succesfully. Printing finished succesfully



and my code that prints is this:



    public static boolean printLPT(String datos[]) throws java.lang.NullPointerException {
        FileOutputStream outputStream = null;
        try {
            String OS = System.getProperty("os.name").toString();
            String defaultPort = SmartClientSettings.getInstance().getSerialPort();
           
            if (!OS.startsWith("Windows")){
                SerialDriver serial = new SerialDriver(defaultPort);

                if(!serial.open()){
                    logger.info("Couldnt open the parallel port!");
                    return false;
                }
            }
           
            logger.info(OS + ": " + defaultPort + " opened succesfully");
            logger.info("Creating StringBuffer...");
            StringBuffer yourText = new StringBuffer();
            logger.info("Appending text");
            for(int i=0; i < datos.length; i++){
                    yourText.append(datos[i]);
            }
            logger.info(yourText);
            logger.info("Converting to Bytes while replacing nulls");
            byte[] bytes = yourText.toString().replace("null","").getBytes();
            logger.info(bytes);
           
       
            logger.info("Opening FileOutputStream");
            outputStream = new FileOutputStream(defaultPort);
            logger.info("Writing to printer");
            outputStream.write(bytes);
           
        } catch (FileNotFoundException fileNotFoundException) {
            logger.error("Could not find the port file : ",fileNotFoundException);
            return false;
        } catch (IOException ioException) {
            logger.error("Couldnt send data to port due to : ",ioException);
            return false;
        }catch (Exception Exception) {
            logger.error("Error while printing to parallel printer port : ",Exception);
            return false;
        }finally{
           
            try{
                logger.info("Closing outputStream...");
                outputStream.close();
                logger.info("outputStream Closed Succesfully. Printing finished succesfully");
                return true;
            } catch (FileNotFoundException fileNotFoundException) {
                logger.error("Could not find the port file : ",fileNotFoundException);
                return false;
            } catch (IOException ioException) {
                logger.error("Couldnt send data to port due to : ",ioException);
                return false;
            }
           
        }
    }



    public synchronized boolean open(){
        boolean abierto=true;
        logger.info("Open Method");
        while (portList.hasMoreElements()) {
            logger.info("Found 1 port");
            portId = (CommPortIdentifier) portList.nextElement();

            if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
                logger.info("and its Serial");
                if (portId.getName().equals(defaultPort)) {

                    logger.info("This is the preferred port ");
                    portFound = true;

                    try {
                        logger.info("Trying to open port with Javax...");
                        serialPort = (SerialPort) portId.open("SimpleWrite", 2000);
                        logger.info("Opened the port Successfully with Javax!!");
                    } catch (Exception e) {

                        logger.error("Couldnt open port with javax", e);
                        JOptionPane.showMessageDialog(null,"Couldnt open the printer port!!","E00156",2);
                        abierto=false;
                        continue;
                    }
                    logger.info("Obtaining OutputStream...");
                    try {
                        outputStream = serialPort.getOutputStream();
                        logger.info("OutputStream OK");
                    } catch (IOException e) {
                        logger.error("Error getting OutputStream port",e);
                        abierto=false;
                    }

                    //try {

                         int impresora = Integer.parseInt(SmartClientSettings.getInstance().getSelectedPrinter());
                         logger.info("Setting Serial parameters");
                         if (impresora == 0){
                            //serialPort.setSerialPortParams(9600, SerialPort.DATABITS_8, SerialPort.STOPBITS_1,SerialPort.PARITY_NONE);
                         }else if(impresora == 1){
                            //serialPort.setSerialPortParams(19200, SerialPort.DATABITS_8, SerialPort.STOPBITS_1,SerialPort.PARITY_NONE);
                         }
                        logger.info("Done setting SerialPort Params");
                    //} catch (UnsupportedCommOperationException e) {
                     //   logger.error("Error setting port parameters", e);
                      //  abierto=false;
                    //}


                    try {
                        serialPort.notifyOnOutputEmpty(true);
                    } catch (Exception e) {
                        logger.error("Error on notifyOnOutputEmpty",e);
                        abierto=false;
                    }

                }
            }else{   //LPT1
                logger.info("and its Parallel");
                if (portId.getName().equals(defaultPort)) {

                    logger.info("This is the preferred port");
                    portFound = true;

                    try {
                        logger.info("Trying to open port with Javax...");
                        parallelPort = (ParallelPort) portId.open("SimpleWrite", 2000);
                        logger.info("Opened the port Successfully with Javax!!");

                    }catch (javax.comm.PortInUseException ex1){
                        logger.error("Used Port Exception: " + portId.isCurrentlyOwned(), ex1 );

                    } catch (Exception e) {

                        logger.error("Couldnt open port with javax", e);
                        abierto=false;
                        continue;
                    }
                    logger.info("Obtaining the OutputStream...");
                    try {
                        outputStream = parallelPort.getOutputStream();
                         logger.info("OutputStream OK");
                    } catch (IOException e) {
                        logger.error("Error getting OutputStream port", e);
                        abierto=false;
                    }


                    try {
                        if (parallelPort.isPaperOut()){
                            Toolkit.getDefaultToolkit().beep();
                        }
                    } catch (Exception e) {
                        logger.error("Error on notifyOnOutputEmpty",e);
                        abierto=false;
                    }

                }


            }
        }

        if (!portFound) {
            abierto=false;
        }

        return abierto;
    }




Can anyone help me?

Nemo