Java Networking Tutorials

package chat;
import java.net.*;
import java.io.*;

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

   public chatServer(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();
         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); 
      }
   }
   public void open() throws IOException
   {  streamIn = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
   }
   public void close() throws IOException
   {  if (socket != null)    socket.close();
      if (streamIn != null)  streamIn.close();
   }
   public static void main(String args[])
   {  chatServer server = null;
      if (args.length != 1)
         System.out.println("Usage: java ChatServer port");
      else
         server = new chatServer(Integer.parseInt(args[0]));
   }
}