One Server Multiple Clients

Question

Hello,
This server code accepts only one client connection at a time. However, I have several lines that are specifically for the server to accept more than one client. What do I need to do in addition for the server to recognize that it can accept more than one client at a time?
import java.io.EOFException;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import java.util.concurrent.Executors;
import java.util.concurrent.ExecutorService;
import javax.swing.JFrame;
public class ServerTest
   public static void main( String args[] )
      Server application = new Server();
      application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
      application.runServer();
class Server extends JFrame
   private JTextField enterField;
   private JTextArea displayArea;
   private ObjectOutputStream output;
   private ObjectInputStream input;
   private ServerSocket server;
   private Socket connection;
   private int counter = 1;
   private ExecutorService serverExecutor;
   private MultiServer clients[];
   public Server()
      super( "Server" );
      enterField = new JTextField();
      enterField.setEditable( false );
      enterField.addActionListener(
         new ActionListener()
            public void actionPerformed( ActionEvent event )
               sendData( event.getActionCommand() );
               enterField.setText( "" );
      add( enterField, BorderLayout.NORTH );
      displayArea = new JTextArea();
      add( new JScrollPane( displayArea ), BorderLayout.CENTER );
      setSize( 300, 150 );
      setVisible( true );
   public void runServer()
      serverExecutor = Executors.newCachedThreadPool();
      try
         server = new ServerSocket( 12345, 100 );
         while ( true )
            try
               waitForConnection();
               getStreams();
               processConnection();
            catch ( EOFException eofException )
               displayMessage( "\nServer terminated connection" );
            finally
               closeConnection();
               counter++;
      catch ( IOException ioException )
         ioException.printStackTrace();
   private void waitForConnection() throws IOException
      displayMessage( "Waiting for connection\n" );
      connection = server.accept(); 
      serverExecutor.execute( new MultiServer(server, connection));     
      displayMessage( "Connection " + counter + " received from: " + connection.getInetAddress().getHostName() );
   private void getStreams() throws IOException
      output = new ObjectOutputStream( connection.getOutputStream() );
      output.flush();
      input = new ObjectInputStream( connection.getInputStream() );
      displayMessage( "\nGot I/O streams\n" );
   private void processConnection() throws IOException
      String message = "Connection successful";
      sendData( message );
      setTextFieldEditable( true );
      serverExecutor.execute(new MultiServer(server, connection));
      do
         try
            message = ( String ) input.readObject();
            displayMessage( "\n" + message );
         catch ( ClassNotFoundException classNotFoundException )
            displayMessage( "\nUnknown object type received" );
      } while ( !message.equals( "CLIENT>>> TERMINATE" ) );
   private void closeConnection()
      displayMessage( "\nTerminating connection\n" );
      setTextFieldEditable( false );
      try
         output.close();
         input.close();
         connection.close();
      catch ( IOException ioException )
         ioException.printStackTrace();
   private void sendData( String message )
      try
         output.writeObject( "SERVER>>> " + message );
         output.flush();
         displayMessage( "\nSERVER>>> " + message );
      catch ( IOException ioException )
         displayArea.append( "\nError writing object" );
   private void displayMessage( final String messageToDisplay )
      SwingUtilities.invokeLater(
         new Runnable()
            public void run()
               displayArea.append( messageToDisplay );
   private void setTextFieldEditable( final boolean editable )
      SwingUtilities.invokeLater(
         new Runnable()
            public void run()
               enterField.setEditable( editable );
  class MultiServer extends Thread
  public MultiServer(ServerSocket servers, Socket connection)
      servers = server;
  public void run(){System.out.print("Yes");}
}

Answer 1

Check out the "Supporting Multiple Clients" bit here: http://java.sun.com/docs/books/tutorial/networking/sockets/clientServer.html
Start a Thread for each client. I'd recommend you create a class:
class Client
    Socket socket;
    ObjectOutputStream out;
    ObjectInputStream in;
    ...any other client-specific data you need...
    public void sendMessage(String s) { ...send to this client...; }
   ...any other client-specific methods you need...;
}Create one of those when accept() gets a new connection, then start the thread for that client.
You may want to keep a LinkedList that contains all the Client objects. E.g. if you want to send a message to all clients you'd loop over the LinkedList and send to each in turn. Synchronize the list appropriately. Removing clients from the list when they close down can be interesting :-) so be careful.