J2ME socket programming

Question

i am doing a final year project in which i have a java program running on pc connected to internet which uses bsnl as an isp.i am provided with a public ip
i have a J2me client.I connect the mobile to internet with gprs.
I use gprs wap settings of vodafone which uses proxies.i have searched internet
and found out that i dont access actual internet using gprs wap. ie we only access wap sites.i want to try purely socket communications.i am using n72 mobile for midlets and socket communications.
sc = (SocketConnection)Connector.open("socket://my bsnl ip:5000");
is = sc.openInputStream();
os = sc.openOutputStream();
i have used simulator and tried communication it was successful.
i tried socket communications form internet client and my server
i also tried different ports too.
now with actual n72 mobile i am having a problem of socket communication.
summary of problems
1.Is direct socket communication possible through gprs with client on N72
with a java server
2.Do i have to use wap settings or internet settings of vodafone

Answer 1

here is my client on mobile..it is same as networkdemo in suns WTK2.5
we used it for testing the connection...
SocketMIdlet:
package socket;
import java.io.*;
import javax.microedition.io.*;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
public class SocketMIDlet extends MIDlet implements CommandListener {
private static final String SERVER = "Server";
private static final String CLIENT = "Client";
private static final String[] names = { SERVER, CLIENT };
private static Display display;
private Form f;
private ChoiceGroup cg;
private boolean isPaused;
private Server server;
private Client client;
private Command exitCommand = new Command("Exit", Command.EXIT, 1);
private Command startCommand = new Command("Start", Command.ITEM, 1);
public SocketMIDlet() {
display = Display.getDisplay(this);
f = new Form("Socket Demo");
cg = new ChoiceGroup("Please select peer", Choice.EXCLUSIVE, names, null);
f.append(cg);
f.addCommand(exitCommand);
f.addCommand(startCommand);
f.setCommandListener(this);
display.setCurrent(f);
public boolean isPaused() {
return isPaused;
public void startApp() {
isPaused = false;
public void pauseApp() {
isPaused = true;
public void destroyApp(boolean unconditional) {
if (server != null) {
server.stop();
if (client != null) {
client.stop();
public void commandAction(Command c, Displayable s) {
if (c == exitCommand) {
destroyApp(true);
notifyDestroyed();
} else if (c == startCommand) {
String name = cg.getString(cg.getSelectedIndex());
if (name.equals(SERVER)) {
server = new Server(this);
server.start();
} else {
client = new Client(this);
client.start();
Client:
package socket;
import java.io.*;
import javax.microedition.io.*;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
public class Client implements Runnable, CommandListener {
private SocketMIDlet parent;
private Display display;
private Form f;
private StringItem si;
private TextField tf;
private boolean stop;
private Command sendCommand = new Command("Send", Command.ITEM, 1);
private Command exitCommand = new Command("Exit", Command.EXIT, 1);
InputStream is;
OutputStream os;
SocketConnection sc;
Sender sender;
public Client(SocketMIDlet m) {
parent = m;
display = Display.getDisplay(parent);
f = new Form("Socket Client");
si = new StringItem("Status:", " ");
tf = new TextField("Send:", "", 30, TextField.ANY);
f.append(si);
f.append(tf);
f.addCommand(exitCommand);
f.addCommand(sendCommand);
f.setCommandListener(this);
display.setCurrent(f);
* Start the client thread
public void start() {
Thread t = new Thread(this);
t.start();
public void run() {
try {
sc = (SocketConnection)Connector.open("socket://59.95.23.211:4000");
si.setText("Connected to server");
is = sc.openInputStream();
os = sc.openOutputStream();
// Start the thread for sending messages - see Sender's main
// comment for explanation
sender = new Sender(os);
// Loop forever, receiving data
while (true) {
StringBuffer sb = new StringBuffer();
int c = 0;
while (((c = is.read()) != '\n') && (c != -1)) {
sb.append((char)c);
if (c == -1) {
break;
// Display message to user
si.setText("Message received - " + sb.toString());
stop();
si.setText("Connection closed");
f.removeCommand(sendCommand);
} catch (ConnectionNotFoundException cnfe) {
Alert a = new Alert("Client", "Please run Server MIDlet first", null, AlertType.ERROR);
a.setTimeout(Alert.FOREVER);
a.setCommandListener(this);
display.setCurrent(a);
} catch (IOException ioe) {
if (!stop) {
ioe.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
public void commandAction(Command c, Displayable s) {
if ((c == sendCommand) && !parent.isPaused()) {
sender.send(tf.getString());
if ((c == Alert.DISMISS_COMMAND) || (c == exitCommand)) {
parent.notifyDestroyed();
parent.destroyApp(true);
* Close all open streams
public void stop() {
try {
stop = true;
if (sender != null) {
sender.stop();
if (is != null) {
is.close();
if (os != null) {
os.close();
if (sc != null) {
sc.close();
} catch (IOException ioe) {
Sender:
package socket;
import java.io.*;
import javax.microedition.io.*;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
public class Sender extends Thread {
private OutputStream os;
private String message;
public Sender(OutputStream os) {
this.os = os;
start();
public synchronized void send(String msg) {
message = msg;
notify();
public synchronized void run() {
while (true) {
// If no client to deal, wait until one connects
if (message == null) {
try {
wait();
} catch (InterruptedException e) {
if (message == null) {
break;
try {
os.write(message.getBytes());
os.write("\r\n".getBytes());
} catch (IOException ioe) {
ioe.printStackTrace();
// Completed client handling, return handler to pool and
// mark for wait
message = null;
public synchronized void stop() {
message = null;
notify();
Server:
package socket;
import java.io.*;
import javax.microedition.io.*;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
public class Server implements Runnable, CommandListener {
private SocketMIDlet parent;
private Display display;
private Form f;
private StringItem si;
private TextField tf;
private boolean stop;
private Command sendCommand = new Command("Send", Command.ITEM, 1);
private Command exitCommand = new Command("Exit", Command.EXIT, 1);
InputStream is;
OutputStream os;
SocketConnection sc;
ServerSocketConnection scn;
Sender sender;
public Server(SocketMIDlet m) {
parent = m;
display = Display.getDisplay(parent);
f = new Form("Socket Server");
si = new StringItem("Status:", " ");
tf = new TextField("Send:", "", 30, TextField.ANY);
f.append(si);
f.append(tf);
f.addCommand(exitCommand);
f.setCommandListener(this);
display.setCurrent(f);
public void start() {
Thread t = new Thread(this);
t.start();
public void run() {
try {
si.setText("Waiting for connection");
scn = (ServerSocketConnection)Connector.open("socket://:4000");
// Wait for a connection.
sc = (SocketConnection)scn.acceptAndOpen();
si.setText("Connection accepted");
is = sc.openInputStream();
os = sc.openOutputStream();
sender = new Sender(os);
// Allow sending of messages only after Sender is created
f.addCommand(sendCommand);
while (true) {
StringBuffer sb = new StringBuffer();
int c = 0;
while (((c = is.read()) != '\n') && (c != -1)) {
sb.append((char)c);
if (c == -1) {
break;
si.setText("Message received - " + sb.toString());
stop();
si.setText("Connection is closed");
f.removeCommand(sendCommand);
} catch (IOException ioe) {
if (ioe.getMessage().equals("ServerSocket Open")) {
Alert a = new Alert("Server", "Port 5000 is already taken.", null, AlertType.ERROR);
a.setTimeout(Alert.FOREVER);
a.setCommandListener(this);
display.setCurrent(a);
} else {
if (!stop) {
ioe.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
public void commandAction(Command c, Displayable s) {
if ((c == sendCommand) && !parent.isPaused()) {
sender.send(tf.getString());
if ((c == Alert.DISMISS_COMMAND) || (c == exitCommand)) {
parent.notifyDestroyed();
parent.destroyApp(true);
* Close all open streams
public void stop() {
try {
stop = true;
if (is != null) {
is.close();
if (os != null) {
os.close();
if (sc != null) {
sc.close();
if (scn != null) {
scn.close();
} catch (IOException ioe) {
Client connects to server...server can send messages to server..but clients
message does not reach server..that it cant be observed on server..how to debug jar file on mobile??