C#

<br />
private void txtEnterPassword_Leave(object sender, System.EventArgs e)<br />
		{<br />
			string queryValidatePwd = "SELECT Username, Password FROM AdminUsers WHERE Username = '" + lblLoginName.Text + "' AND Password = '" + txtEnterPassword.Text + "' ";<br />
<br />
			try<br />
			{<br />
				OleDbCommand cmdValidatePwd = cnnChangePassword.CreateCommand();<br />
				cmdValidatePwd.CommandType = CommandType.Text;<br />
				cmdValidatePwd.CommandText = queryValidatePwd;<br />
<br />
				OleDbDataAdapter daValidatePwd = new OleDbDataAdapter(cmdValidatePwd);<br />
				DataTable dtValidatePwd = new DataTable("AdminUsers");<br />
				<br />
				int count = daValidatePwd.Fill(dtValidatePwd);<br />
				if ( daValidatePwd.Fill(dtValidatePwd) == 1 ) //Password is correct<br />
				{<br />
					txtEnterNewPassword.Visible = true;<br />
					txtEnterNewPassword.Focus(); //Get focus of next text box.<br />
				}<br />
				else<br />
				{<br />
					MessageBox.Show("Password is incorrect for this username - please try again","Incorrect Password",MessageBoxButtons.OK,MessageBoxIcon.Warning);<br />
					txtEnterPassword.Clear();<br />
					txtEnterPassword.Focus();<br />
				}<br />
				dtValidatePwd.Dispose();<br />
				daValidatePwd.Dispose();		<br />
			}<br />
			catch ( OleDbException ex )<br />
			{<br />
				MessageBox.Show(ex.Message);<br />
			}<br />
			catch ( Exception ex )<br />
			{<br />
				MessageBox.Show(ex.Message);<br />
			}<br />
		}<br />

<br />
private void btnCancel_Click(object sender, System.EventArgs e)<br />
{<br />
	this.Dispose();<br />
}<br />

Java Based Server: 
---------------------- 
import java.net.*; 
import java.io.*; 
import java.util.*; 

public class ChatServer { 
  public ChatServer (int port) throws IOException { 
    ServerSocket server = new ServerSocket (port); 
    while (true) { 
      Socket client = server.accept (); 
      System.out.println ("Accepted from " + client.getInetAddress ()); 
      ChatHandler c = new ChatHandler (client); 
      c.start (); 
    } 
  } 

  public static void main (String args[]) throws IOException { 
    new ChatServer (1098); 
  } 
} 


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

public class ChatHandler extends Thread { 
  protected Socket s; 
  protected DataInputStream i; 
  protected DataOutputStream o; 

  public ChatHandler (Socket s) throws IOException { 
    this.s = s; 
    i = new DataInputStream (new BufferedInputStream 
(s.getInputStream())); 
    o = new DataOutputStream (new BufferedOutputStream 
(s.getOutputStream())); 
  } 

  protected static Vector handlers = new Vector (); 

  public void run () { 
    String name = s.getInetAddress ().toString (); 
    try { 
      System.out.println(name + " has joined."); 
      handlers.addElement (this); 
      while (true) { 
        System.out.println("Waiting for data..."); 
        String msg = i.readUTF (); 
        System.out.println(name + " - " + msg); 
      } 
    } catch (IOException ex) { 
      ex.printStackTrace (); 
    } finally { 
      handlers.removeElement (this); 
      System.out.println(name + " has left."); 
      try { 
        s.close (); 
      } catch (IOException ex) { 
        ex.printStackTrace(); 
      } 
    } 
  } 

C# Client 
---------------------- 
using System; 
using System.Threading; 
using System.Net.Sockets; 
using System.IO; 
using System.Data; 
using System.Net; 
using System.Text; 

namespace TCPClient 
{ 
        /// <summary> 
        /// Summary description for Class1. 
        /// </summary> 
        class Client 
        { 
                static NetworkStream output; 
                static BinaryWriter writer; 
                static BinaryReader reader; 
                static Thread readThread; 


                /// <summary> 
                /// The main entry point for the application. 
                /// </summary> 
                [STAThread] 
                static void Main(string[] args) 
                { 
                        string msg; 
                        TcpClient client; 


                        client = new TcpClient(); 
                        client.Connect( "localhost", 1098 ); 
                        output = client.GetStream(); 


                        // create objects for writing and reading across stream 
                        writer = new BinaryWriter(output, System.Text.Encoding.UTF8); 
                        reader = new BinaryReader(output); 


                        //Start thread to recieve data back from server... 
                        readThread = new Thread(new ThreadStart(RunClient)); 
                        readThread.Start(); 


                        // get text from colsole to send until just the ENTER key pressed... 


                        do 
                        { 


                                Console.Write("Text to send: "); 
                                msg = Console.ReadLine(); 
                                if (msg == "") 
                                        break; 


                                Byte[] byteDateLine = Encoding.ASCII.GetBytes( msg.ToCharArray() ); 
                                writer.Write(byteDateLine, byteDateLine.Length, 0 ); 


                        } while (true); 


                        Console.WriteLine("Closing connection"); 


                        readThread.Abort(); 
                        writer.Close(); 
                        reader.Close(); 
                        output.Close(); 
                        client.Close(); 
                } 


                static void RunClient() 
                { 
                        string msg; 


                        try 
                        { 
                                Console.WriteLine("Waiting for data from server..."); 
                                do 
                                { 
                                        msg = reader.ReadString(); 
                                        Console.WriteLine(msg); 
                                } while (true); 


                        } 
                        catch ( Exception error ) 
                        { 
                                Console.WriteLine( error.ToString() ); 
                        } 


                } 

        }