reading from TCP socket problem

[Michal Bury]

Hi I am new with TCP socket's.
My problem is as follows:
I tried a sample program that listen as a server on desired port, read data from socket and send the data back (see code). But nothing happens. In network monitor I can see that the data from client are comming but nothing is sended back.
Can anybody help to understand where is my problem.

thanks

import java.io.*;
import java.net.*;
 
public class echo3 {
    public static void main(String args[]) {
 
// declaration section:
// declare a server socket and a client socket for the server
// declare an input and an output stream
 
        ServerSocket echoServer = null;
        String line;
        DataInputStream is;
        PrintStream os;
        Socket clientSocket = null;
 
// Try to open a server socket on port 9999
// Note that we can't choose a port less than 1023 if we are not
// privileged users (root)
 
        try {
           echoServer = new ServerSocket(2101);
        }
        catch (IOException e) {
           System.out.println(e);
        }  
 
// Create a socket object from the ServerSocket to listen and accept
// connections.
// Open input and output streams
 
try {
           clientSocket = echoServer.accept();
           is = new DataInputStream(clientSocket.getInputStream());
           os = new PrintStream(clientSocket.getOutputStream());
 
// As long as we receive data, echo that data back to the client.
 
           while (true) {
             if (clientSocket.isConnected()) {
                os.println("your are connected");
             }
               
               line = is.readLine();
             os.println(line);
           }
        }  
catch (IOException e) {
           System.out.println(e);
        }
    }
}

[Joe Ess]

The code looks fine to me. What do you mean by "nothing happens"?
How about putting in additional System.out.println() messages, for example immediately before and after echoServer.accept() and after the while(true) loop. That will help you establish if the code is doing what you think it is doing.
One thing I notice is that this code will only handle one client. Ever. So if you hooked up once and didn't restart the server, your next client will not be serviced (though I'd expect the while(true) to exit with an exception when the first client exited. . .)

[Michal Bury]

Ok. I found the problem. It was on the Client side. It sended data without
"end of line", therefore I can not use readln() but only read.