Java server and C# Client (Can't exchange data)

I recently started to learn java. I was writing an android app with a 'chat' feature. I wanted to have a java chat server and the client code will be from C#. This is the Java server code,

    import java.net.*;
import java.io.*;


public class server 
{
    private Socket socket = null;
    private ServerSocket server = null;
    private DataInputStream streamIn = null;
    private DataOutputStream streamOut = null;

    public server(int port)
    {
        try
        {
            System.out.println("Binding to port " + port + ", please wait ...");
            server = new ServerSocket(port);
            System.out.println("Server started: " + server);
            System.out.println("Waiting for a client ...");
            socket = server.accept();
            System.out.println("Client accepted: " + socket);



            open(); // Custom method
            boolean done = false;
            while(!done)
            {
                try
                {
                    String line = streamIn.readUTF();
                    System.out.println(line);
                    done = line.equals(".bye");
                }
                catch(IOException ioe)
                {
                    done = true;
                }
            }
            close();
        }
        catch(IOException ioe)
        {
            System.out.println(ioe);
        }

    }

    private void close() throws IOException
    {
        if (socket != null) socket.close();
        if(streamIn != null) streamIn.close();
    }

    public void open() throws IOException
    {
        streamIn = new DataInputStream(new  BufferedInputStream(socket.getInputStream()));
        //streamOut = new DataOutputStream(socket.getOutputStream());
        //streamOut.writeUTF("Hello");
        //streamOut.flush();
        //System.out.println("Message sent");
    }

    public static void main(String args[])
    {
        server ss = null;
        if(args.length != 1)
        {
            System.out.println("Usage: java ChatServer port");
        }
        else
        {
            ss = new server(Integer.parseInt(args[0]));
        }
    }

}

above code is run using eclipse and I used networkstream and StreamReader in my C# client app, but I could connect to the server using TCPClient but the streamreader or networkstream didn't work.

C# code

private static TcpClient client;
private static BinaryWriter writer;
private const int MAX_BUFFER_SIZE = 1024;

private static void Main(string[] args)
{
    try
    {
        Console.WriteLine("Connecting to the server");
        client = new TcpClient();
        client.Connect("127.0.0.1", 8888);
        writer = new BinaryWriter(client.GetStream());
        Console.WriteLine("Connected to the server");
        Console.WriteLine("Sending hello world");

        WriteString(writer, "Hello World!");

    }
    catch (Exception ex)
    {
        Console.WriteLine(ex.Message);
    }

    Console.Read();
}

public static void WriteString(BinaryWriter os, string value)
{
    if (value != null)
    {
        byte[] array = System.Text.Encoding.Unicode.GetBytes(value);
        WriteBuffer(os, array);
    }
    else
    {
        WriteInt(os, 0);
    }
}

public static void WriteBuffer(BinaryWriter os, byte[] array)
{
    if ((array != null) && (array.Length > 0) && (array.Length <  MAX_BUFFER_SIZE))
    {
        WriteInt(os, array.Length);
        os.Write(array);
    }
    else
    {
        WriteInt(os, 0);
    }
}

public static void WriteInt(BinaryWriter outStream, int value)
{
    byte[] buffer = BitConverter.GetBytes(value);

    outStream.Write(buffer);
}

above code is from link I also found in stack, some codes that used networkstream but I got no luck. I have already written a C# chat app using StreamWriter/reader. Any help is appreciated/. the server works, java client is working very well with it. (I have a little experience with C#, but not with Java )

Thanks

Edit:- I found it is related to the difference of encoding the classes use. Source