Question

The socket server listed in step 3 from http://pirate.shu.edu/~wachsmut/Teaching/CSAS2214/Virtual/Lectures/chat-client-server.html builds cleanly (java version “1.7.0_02”) and runs without error but it exits without error instead of waiting to accept clients.

Updated ChatServer with missing arg code:

ChatServer:

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

public class ChatServer implements Runnable
{  private ServerSocket     server = null;
   private Thread           thread = null;
   private ChatServerThread client = 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);
         start();
      }
      catch(IOException ioe)
      {  System.out.println(ioe); }
   }
   public void run()
   {  while (thread != null)
      {  try
         {  System.out.println("Waiting for a client ...");
            addThread(server.accept());
         }
         catch(IOException ie)
         {  System.out.println("Acceptance Error: " + ie); }
      }
   }
   public void addThread(Socket socket)
   {  System.out.println("Client accepted: " + socket);
      client = new ChatServerThread(this, socket);
      try
      {  client.open();
         client.start();
      }
      catch(IOException ioe)
      {  System.out.println("Error opening thread: " + ioe); }
   }
   public void start() {
   thread = new Thread(this);
   thread.start();
 }
   public void stop()                    { /* no change */ }
   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]));
 }
}

ChatServerThread:

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

public class ChatServerThread extends Thread
{  private Socket          socket   = null;
   private ChatServer      server   = null;
   private int             ID       = -1;
   private DataInputStream streamIn =  null;

   public ChatServerThread(ChatServer _server, Socket _socket)
   {  server = _server;  socket = _socket;  ID = socket.getPort();
   }
   public void run()
   {  System.out.println("Server Thread " + ID + " running.");
      while (true)
      {  try
         {  System.out.println(streamIn.readUTF());
         }
         catch(IOException ioe) {
            System.out.println(ioe.getMessage());
         }
      }
   }
   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();
   }
}

Answer 1

EDIT: Updating my answer with a working solution.

Change these methods in your ChatServer class in order to be like these

public void start() {
    thread = new Thread(this);
    thread.start();
}

public void stop() { 
    // You should implement this too
}

public static void main(String args[]) { 
    // Instantiate a CharServer with the listening port 9191
    ChatServer chatServer = new ChatServer(9191);
    // CharServer.start() should not be confused with Thread.start();
    // This calls our custom method up above, which includes a call to
    // Thread(ChatServer).start();
    chatServer.start();

}

Where 9191 is a port number I made up.

Executing CharServer#main method produces the following output and stays alive

Binding to port 9191, please wait  ...
Server started: ServerSocket[addr=0.0.0.0/0.0.0.0,port=0,localport=9191]
Waiting for a client ...
Waiting for a client ...

You should also implement stop() method for the sake of functionality.