Originally Posted by Clawsy

Hello,
I'm working on a bluetooth chat application project called 'BlueChat'. I coded the server (BServer.java) and client (BClient.java) parts (2 separate threads). The visual part is called BlueChat.java and allowes the user to select to be the server or the client.

I wrote a lot of System.out.println("")'s to check WHY NO MESSAGE IS SEND (there are no errors or exceptions). So I detect that:
- On the server, when it reaches

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con = notifier.acceptAndOpen();

con = notifier.acceptAndOpen();

part, loopes infinitely as it doesn't receive any join from a 'Client'
- On the client when it passes the 'inquiry' but it's waiting infinitely on the service detection:

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serviceL.wait();

serviceL.wait();

as it can never find a remote host device (the server)


Here are the classes:
The 'visual' class

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public class BlueChat extends MIDlet implements CommandListener{
 
 
    /*******************************************************************************/
 
 
    private final Command EXIT_CMD = new Command("Exit", Command.EXIT, 2);
 
 
 
 
    Command RECEIVE_CMD = new Command("Receive", Command.ITEM, 2);
    Command SEND_CMD = new Command("Send", Command.ITEM, 2);
 
 
 
    /** value is true after creating the server/client */
    private boolean isInit = false;
 
    /*******************************************************************************/
 
 
 
    Display display;
    Form mainForm;
    boolean firstTime = true;
 
    StringItem status;
 
 
    //Bluetooth members
 
 
    LocalDevice local = null;
    DiscoveryAgent discoveryAgent = null;
    ServiceRecord SR = null;
 
    L2CAPConnectionNotifier notifier = null;
    L2CAPConnection con = null;
    String service_UUID = null;
 
    InputStream input = null;
    OutputStream output = null;
 
 
 
    String deviceName="",deviceAddress="";
    private boolean listening=true;
    private StringItem msg;
 
 
    //<editor-fold defaultstate="collapsed" desc=" Generated Fields ">                      
    //</editor-fold>                    
 
    /**
     * The BlueChat constructor.
     */
    public BlueChat() {
 
    }
 
 
   protected void setAlert(String info) {
        Alert a = new Alert("INFO");
        a.setString(info);
        a.setTimeout(Alert.FOREVER);
        display.setCurrent(a);
    }
 
  ...
    public void switchDisplayable(Alert alert, Displayable nextDisplayable) {                                            
        // write pre-switch user code here
        Display display = getDisplay();                                               
        if (alert == null) {
            display.setCurrent(nextDisplayable);
        } else {
            display.setCurrent(alert, nextDisplayable);
        }                                             
        // write post-switch user code here
    }                                   
    //</editor-fold>                                 
 
    /**
     * Returns a display instance.
     * @return the display instance.
     */
    public Display getDisplay () {
        return Display.getDisplay(this);
    }
 
    /**
     * Exits MIDlet.
     */
    public void exitMIDlet() {
        switchDisplayable (null, null);
        destroyApp(true);
        notifyDestroyed();
    }
 
    /**
     * Called when MIDlet is started.
     * Checks whether the MIDlet have been already started and initialize/starts or resumes the MIDlet.
     */
    public void startApp() {
 
       firstTime = true;
       mainForm = new Form("BlueChat");
 
       if(firstTime)
       {
           display = Display.getDisplay(this);
           // vizual
           status = new StringItem("Status:", "...");
           mainForm.append(status);
           msg = new StringItem("Message:","...");
           mainForm.append(msg);
 
           //comenzi
           mainForm.addCommand(EXIT_CMD);
           mainForm.addCommand(SEND_CMD);
           mainForm.addCommand(RECEIVE_CMD);
 
 
           mainForm.setCommandListener(this);
 
            /////////////////
           firstTime = false;
       }
 
       display.setCurrent(mainForm);
       /* try {
            connect();
        } catch (IOException ex) {
            ex.printStackTrace();
        }*/
    }
 
    public void commandAction(Command c, Displayable d)
    {
        if(c == EXIT_CMD)
        {    
            this.destroyApp(true);
            this.notifyDestroyed();
 
        }
        else if(c == RECEIVE_CMD)
        {
           new BServer(this);
 
        }
        else if(c == SEND_CMD)
        {
           new BClient(this);
        }
 
 
 
    }
 
    /**
     * Called when MIDlet is paused.
     */
    public void pauseApp() {
        midletPaused = true;
    }
 
    /**
     * Called to signal the MIDlet to terminate.
     * @param unconditional if true, then the MIDlet has to be unconditionally terminated and all resources has to be released.
     */
    public void destroyApp(boolean unconditional) {
    }
 
 
 
}

public class BlueChat extends MIDlet implements CommandListener{ /*******************************************************************************/ private final Command EXIT_CMD = new Command("Exit", Command.EXIT, 2); Command RECEIVE_CMD = new Command("Receive", Command.ITEM, 2); Command SEND_CMD = new Command("Send", Command.ITEM, 2); /** value is true after creating the server/client */ private boolean isInit = false; /*******************************************************************************/ Display display; Form mainForm; boolean firstTime = true; StringItem status; //Bluetooth members LocalDevice local = null; DiscoveryAgent discoveryAgent = null; ServiceRecord SR = null; L2CAPConnectionNotifier notifier = null; L2CAPConnection con = null; String service_UUID = null; InputStream input = null; OutputStream output = null; String deviceName="",deviceAddress=""; private boolean listening=true; private StringItem msg; //<editor-fold defaultstate="collapsed" desc=" Generated Fields "> //</editor-fold> /** * The BlueChat constructor. */ public BlueChat() { } protected void setAlert(String info) { Alert a = new Alert("INFO"); a.setString(info); a.setTimeout(Alert.FOREVER); display.setCurrent(a); } ... public void switchDisplayable(Alert alert, Displayable nextDisplayable) { // write pre-switch user code here Display display = getDisplay(); if (alert == null) { display.setCurrent(nextDisplayable); } else { display.setCurrent(alert, nextDisplayable); } // write post-switch user code here } //</editor-fold> /** * Returns a display instance. * @return the display instance. */ public Display getDisplay () { return Display.getDisplay(this); } /** * Exits MIDlet. */ public void exitMIDlet() { switchDisplayable (null, null); destroyApp(true); notifyDestroyed(); } /** * Called when MIDlet is started. * Checks whether the MIDlet have been already started and initialize/starts or resumes the MIDlet. */ public void startApp() { firstTime = true; mainForm = new Form("BlueChat"); if(firstTime) { display = Display.getDisplay(this); // vizual status = new StringItem("Status:", "..."); mainForm.append(status); msg = new StringItem("Message:","..."); mainForm.append(msg); //comenzi mainForm.addCommand(EXIT_CMD); mainForm.addCommand(SEND_CMD); mainForm.addCommand(RECEIVE_CMD); mainForm.setCommandListener(this); ///////////////// firstTime = false; } display.setCurrent(mainForm); /* try { connect(); } catch (IOException ex) { ex.printStackTrace(); }*/ } public void commandAction(Command c, Displayable d) { if(c == EXIT_CMD) { this.destroyApp(true); this.notifyDestroyed(); } else if(c == RECEIVE_CMD) { new BServer(this); } else if(c == SEND_CMD) { new BClient(this); } } /** * Called when MIDlet is paused. */ public void pauseApp() { midletPaused = true; } /** * Called to signal the MIDlet to terminate. * @param unconditional if true, then the MIDlet has to be unconditionally terminated and all resources has to be released. */ public void destroyApp(boolean unconditional) { } }

The SERVER class

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public class BServer implements Runnable{
    private LocalDevice local;
    private DiscoveryAgent discoveryAgent;
    private String deviceName;
    private String deviceAddress;
   // final private StringItem status,msg;
    private String service_UUID="00000000000010008000006057028A06";
    private L2CAPConnectionNotifier notifier;
    private boolean listening;
    private L2CAPConnection con;
 
    private BlueChat chat;
 
    BServer(BlueChat chat)
    {
 
            this.chat = chat;
 
            Thread t = new Thread(this);
            t.start();
    }
 
    public void run() {
  try {
       System.out.println("Server thread started");
        local = LocalDevice.getLocalDevice();//initializare  pt gazda
        local.setDiscoverable(DiscoveryAgent.LIAC);
        discoveryAgent = local.getDiscoveryAgent();
        deviceName = local.getFriendlyName();
        deviceAddress = local.getBluetoothAddress();
 
       /* status.setText(deviceName+"\nAddress="+deviceAddress+
                "\nDiscovery agent="+discoveryAgent.toString());
*/
 
 
 
       String url = "btl2cap://localhost:"+service_UUID+";name="+deviceName;
 
            notifier = (L2CAPConnectionNotifier) Connector.open(url);
            // con = (L2CAPConnection)Connector.open(url);
 
       System.out.println("advertising the connection");
/**************************************************************
                                                       WAITING INFINETELY HERE
*******************************************************/
       con = notifier.acceptAndOpen();///////////////////////////////
        System.out.println("advertising finished");
       while(listening){
 
        if(con.ready()){
             System.out.println("server READY to receive data");
            // primim in bytes data de la client apoi o trecem intr-un String
            byte[] buff  = new byte[1000];
            con.receive(buff);
 
            String s = new String(buff,0, buff.length);
          //  msg.setText("a");
            //daca am primit mesaj alertam interfata vizuala
            System.out.println("Recieved from client: " + s.trim());
            chat.setAlert(s.trim());
 
            //asa trimitem
            sendMessage("Hello client, my name is: " + local.getFriendlyName());
 
            listening = false;
        }
       }
 
 
               } catch (IOException ex) {
                   System.out.println("Eroare la SERVER\n");
            ex.printStackTrace();
        }
 
 
 
    }
 
 
    private void sendMessage(String msg)
    {
        byte[] buff = msg.getBytes();
                try {
            con.send(buff);
        } catch(IOException e){
            System.out.println(e);
        }
    }
 
}

public class BServer implements Runnable{ private LocalDevice local; private DiscoveryAgent discoveryAgent; private String deviceName; private String deviceAddress; // final private StringItem status,msg; private String service_UUID="00000000000010008000006057028A06"; private L2CAPConnectionNotifier notifier; private boolean listening; private L2CAPConnection con; private BlueChat chat; BServer(BlueChat chat) { this.chat = chat; Thread t = new Thread(this); t.start(); } public void run() { try { System.out.println("Server thread started"); local = LocalDevice.getLocalDevice();//initializare pt gazda local.setDiscoverable(DiscoveryAgent.LIAC); discoveryAgent = local.getDiscoveryAgent(); deviceName = local.getFriendlyName(); deviceAddress = local.getBluetoothAddress(); /* status.setText(deviceName+"\nAddress="+deviceAddress+ "\nDiscovery agent="+discoveryAgent.toString()); */ String url = "btl2cap://localhost:"+service_UUID+";name="+deviceName; notifier = (L2CAPConnectionNotifier) Connector.open(url); // con = (L2CAPConnection)Connector.open(url); System.out.println("advertising the connection"); /************************************************************** WAITING INFINETELY HERE *******************************************************/ con = notifier.acceptAndOpen();/////////////////////////////// System.out.println("advertising finished"); while(listening){ if(con.ready()){ System.out.println("server READY to receive data"); // primim in bytes data de la client apoi o trecem intr-un String byte[] buff = new byte[1000]; con.receive(buff); String s = new String(buff,0, buff.length); // msg.setText("a"); //daca am primit mesaj alertam interfata vizuala System.out.println("Recieved from client: " + s.trim()); chat.setAlert(s.trim()); //asa trimitem sendMessage("Hello client, my name is: " + local.getFriendlyName()); listening = false; } } } catch (IOException ex) { System.out.println("Eroare la SERVER\n"); ex.printStackTrace(); } } private void sendMessage(String msg) { byte[] buff = msg.getBytes(); try { con.send(buff); } catch(IOException e){ System.out.println(e); } } }

The client class

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public class BClient implements Runnable{
 
    String s;
    private LocalDevice local;
    private DiscoveryAgent discoveryAgent;
    private String deviceName;
    private String deviceAddress;
 
    private String service_UUID="00000000000010008000006057028A06";
    private L2CAPConnectionNotifier notifier;
    private L2CAPConnection con;
 
    private BlueChat chat;
    private InquiryListener inquiryL;
    private ServiceListener serviceL;
    private boolean listening=true;
 
    BClient(BlueChat chat)
    {
       this.chat = chat;
 
        Thread t = new Thread(this);
        t.start();
    }
 
    public void run() {
       try{
          byte[] buff = "SAALUT".getBytes();
 
          System.out.println("Client thread started");
        //date dispozitiv
        local = LocalDevice.getLocalDevice();//initializare  pt gazda
        local.setDiscoverable(DiscoveryAgent.LIAC);
        discoveryAgent = local.getDiscoveryAgent();
        deviceName = local.getFriendlyName();
        deviceAddress = local.getBluetoothAddress();
 
        //cautare dispozitive bluetooth apoi serviciile fiecaruia
        inquiryL = new InquiryListener();
 
        synchronized(inquiryL){
            System.out.println("inainte de cautare inquiry");
            discoveryAgent.startInquiry(DiscoveryAgent.LIAC, inquiryL);
            try{
                System.out.println("in asteptare");
                inquiryL.wait();
            }catch(InterruptedException e){ }
 
 
            System.out.println("asteptare inquiry terminata");
        }
 
        //dispozitive gasite - in obiectul de cautare de mai sus
        Enumeration devices = inquiryL.cached_devices.elements();
 
        UUID[] u = new UUID[]{ new UUID("00000000000010008000006057028A06", false) };
        int attributes[]= { 0x0100 };
 
        //acum serviciile aferente FIECARUI ELEMENT... deic traversam vectorul de elemente
        serviceL = new ServiceListener();
        while(devices.hasMoreElements()){
            synchronized(serviceL){
                System.out.println("inainte de cautare servicii");
                discoveryAgent.searchServices(attributes, u, (RemoteDevice)devices.nextElement(), inquiryL);
                try{
                    System.out.println("in asteptare");
/**************************************************************
                                                       WAITING INFINETELY HERE
*******************************************************/
                    serviceL.wait();///////////
                }catch(InterruptedException e){}
 
                System.out.println("asteptare servicii terminata");
            }
 
 
         if (serviceL.service!=null){
            try {
                String url;
                url = serviceL.service.getConnectionURL(0, false);
                deviceName = LocalDevice.getLocalDevice().getFriendlyName();
                con = (L2CAPConnection) Connector.open( url );
                sendMessage("Hello server, my name is: " + deviceName);
 
                byte[] b = new byte[1000];
 
                 System.out.println("IN SERVICIU");
 
                while (listening) {
                    if (con.ready()){
                         System.out.println("GATA DE PRIMIRE");
 
                        con.receive(b);
                        String str = new String(b, 0, b.length);
                        System.out.println("Received from server: " + str.trim());
                        chat.setAlert(str.trim());
                        listening = false;
                    }
                }
            } catch (IOException g) {System.out.println(g);}
        }
 
 
        }
 
 
         } catch (IOException ex) {
              System.out.println("Eroare la CLIENT\n");
            ex.printStackTrace();
        }
    }
 
 
 
 
   /********* TRIMITE *****************/
 
   private void sendMessage(String msg)
    {
        byte[] buff = msg.getBytes();
                try {
            con.send(buff);
        } catch(IOException e){
            System.out.println(e);
        }
    }
 
 
 
   /*********** CLASA PENTRU CAUTARE DISPOZITIVE*******/
    class InquiryListener implements DiscoveryListener{
 
        public Vector cached_devices;
 
        InquiryListener(){
             cached_devices = new Vector();
        }
 
        public void deviceDiscovered(RemoteDevice btDevice, DeviceClass cod) {
           if( ! cached_devices.contains( btDevice ) )	{
            cached_devices.addElement( btDevice );
          }
        }
 
        public void servicesDiscovered(int transID, ServiceRecord[] servRecord) {
        }
 
        public void serviceSearchCompleted(int transID, int respCode) {  
        }
 
        public void inquiryCompleted(int discType) {
             synchronized(this){ this.notify();System.out.println("inquiry terminata"); }
        }
 
    }
 
 
 
    /*********** CLASA PENTRU CAUTARE SERVICII ale dispozitivelor*******/
    class ServiceListener implements DiscoveryListener{
 
        public ServiceRecord service;
 
        public void servicesDiscovered(int transID, ServiceRecord[] servRecord) {
                   service = servRecord[0];
                    System.out.println("foundService");
        }
 
        public void serviceSearchCompleted(int transID, int respCode) {
           synchronized( this ){	this.notify();}
        }
 
 
        public void inquiryCompleted(int discType) {
        }
 
        public void deviceDiscovered(RemoteDevice btDevice, DeviceClass cod) {
        }
 
    }
 
 
}

public class BClient implements Runnable{ String s; private LocalDevice local; private DiscoveryAgent discoveryAgent; private String deviceName; private String deviceAddress; private String service_UUID="00000000000010008000006057028A06"; private L2CAPConnectionNotifier notifier; private L2CAPConnection con; private BlueChat chat; private InquiryListener inquiryL; private ServiceListener serviceL; private boolean listening=true; BClient(BlueChat chat) { this.chat = chat; Thread t = new Thread(this); t.start(); } public void run() { try{ byte[] buff = "SAALUT".getBytes(); System.out.println("Client thread started"); //date dispozitiv local = LocalDevice.getLocalDevice();//initializare pt gazda local.setDiscoverable(DiscoveryAgent.LIAC); discoveryAgent = local.getDiscoveryAgent(); deviceName = local.getFriendlyName(); deviceAddress = local.getBluetoothAddress(); //cautare dispozitive bluetooth apoi serviciile fiecaruia inquiryL = new InquiryListener(); synchronized(inquiryL){ System.out.println("inainte de cautare inquiry"); discoveryAgent.startInquiry(DiscoveryAgent.LIAC, inquiryL); try{ System.out.println("in asteptare"); inquiryL.wait(); }catch(InterruptedException e){ } System.out.println("asteptare inquiry terminata"); } //dispozitive gasite - in obiectul de cautare de mai sus Enumeration devices = inquiryL.cached_devices.elements(); UUID[] u = new UUID[]{ new UUID("00000000000010008000006057028A06", false) }; int attributes[]= { 0x0100 }; //acum serviciile aferente FIECARUI ELEMENT... deic traversam vectorul de elemente serviceL = new ServiceListener(); while(devices.hasMoreElements()){ synchronized(serviceL){ System.out.println("inainte de cautare servicii"); discoveryAgent.searchServices(attributes, u, (RemoteDevice)devices.nextElement(), inquiryL); try{ System.out.println("in asteptare"); /************************************************************** WAITING INFINETELY HERE *******************************************************/ serviceL.wait();/////////// }catch(InterruptedException e){} System.out.println("asteptare servicii terminata"); } if (serviceL.service!=null){ try { String url; url = serviceL.service.getConnectionURL(0, false); deviceName = LocalDevice.getLocalDevice().getFriendlyName(); con = (L2CAPConnection) Connector.open( url ); sendMessage("Hello server, my name is: " + deviceName); byte[] b = new byte[1000]; System.out.println("IN SERVICIU"); while (listening) { if (con.ready()){ System.out.println("GATA DE PRIMIRE"); con.receive(b); String str = new String(b, 0, b.length); System.out.println("Received from server: " + str.trim()); chat.setAlert(str.trim()); listening = false; } } } catch (IOException g) {System.out.println(g);} } } } catch (IOException ex) { System.out.println("Eroare la CLIENT\n"); ex.printStackTrace(); } } /********* TRIMITE *****************/ private void sendMessage(String msg) { byte[] buff = msg.getBytes(); try { con.send(buff); } catch(IOException e){ System.out.println(e); } } /*********** CLASA PENTRU CAUTARE DISPOZITIVE*******/ class InquiryListener implements DiscoveryListener{ public Vector cached_devices; InquiryListener(){ cached_devices = new Vector(); } public void deviceDiscovered(RemoteDevice btDevice, DeviceClass cod) { if( ! cached_devices.contains( btDevice ) ) { cached_devices.addElement( btDevice ); } } public void servicesDiscovered(int transID, ServiceRecord[] servRecord) { } public void serviceSearchCompleted(int transID, int respCode) { } public void inquiryCompleted(int discType) { synchronized(this){ this.notify();System.out.println("inquiry terminata"); } } } /*********** CLASA PENTRU CAUTARE SERVICII ale dispozitivelor*******/ class ServiceListener implements DiscoveryListener{ public ServiceRecord service; public void servicesDiscovered(int transID, ServiceRecord[] servRecord) { service = servRecord[0]; System.out.println("foundService"); } public void serviceSearchCompleted(int transID, int respCode) { synchronized( this ){ this.notify();} } public void inquiryCompleted(int discType) { } public void deviceDiscovered(RemoteDevice btDevice, DeviceClass cod) { } } }

So please help me on detection between devices if you can. I just don't know why the don't detect each other. I use NetBeans with Mobile Simulator and I even tested it on two real mobile phones - nothing happened

Originally Posted by susman

Hello,
I'm a novice in J2ME but i started developing a bluetooth chat aplication. I managed to find some samples of btooth chat aplications but i'm not satisfied with it. Can you provide some help(i mean source code )? if i can help you with your problem i'll send you a solution.
Thank you

Originally Posted by Clawsy

Just download the wirelesss development kit for java and, after you install it ouy'll find a folder with a lot of examples there. As for my problem, I abandoned L2CAP connection and used StreamConnection. Good Luck. In fact, this is an old unsolved thread.