Thread: JAVA NETWORK client/server architechture

ok. so this is the Server and client code snippet. please can someone else run it and tell me why my code is giving this much trouble. am using a windows 7 64-bit system on a jdk 7U40 installer. my firewall is turned off from both windows and my antivirus program.
below is the code;

Server class

// Fig. 27.5: Server.java
// Server portion of a client/server stream-socket connection. 
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;
 
public class Server extends JFrame 
{
   private JTextField enterField; // inputs message from user
   private JTextArea displayArea; // display information to user
   private ObjectOutputStream output; // output stream to client
   private ObjectInputStream input; // input stream from client
   private ServerSocket server; // server socket
   private Socket connection; // connection to client
   private int counter = 1; // counter of number of connections
 
   // set up GUI
   public Server()
   {
      super( "Server" );
 
      enterField = new JTextField(); // create enterField
      enterField.setEditable( false );
      enterField.addActionListener(
         new ActionListener() 
         {
            // send message to client
            public void actionPerformed( ActionEvent event )
            {
               sendData( event.getActionCommand() );
               enterField.setText( "" );
            } // end method actionPerformed
         } // end anonymous inner class
      ); // end call to addActionListener
 
      add( enterField, BorderLayout.NORTH );
 
      displayArea = new JTextArea(); // create displayArea
      add( new JScrollPane( displayArea ), BorderLayout.CENTER );
 
      setSize( 300, 150 ); // set size of window
      setVisible( true ); // show window
   } // end Server constructor
 
   // set up and run server 
   public void runServer()
   {
      try // set up server to receive connections; process connections
      {
         server = new ServerSocket(12345,100); // create ServerSocket
 
         while ( true ) 
         {
            try 
            {
               waitForConnection(); // wait for a connection
               getStreams(); // get input & output streams
               processConnection(); // process connection
            } // end try
            catch ( EOFException eofException ) 
            {
               displayMessage( "\nServer terminated connection" );
            } // end catch
            finally 
            {
               closeConnection(); //  close connection
               ++counter;
            } // end finally
         } // end while
      } // end try
      catch ( IOException ioException ) 
      {
         ioException.printStackTrace();
      } // end catch
   } // end method runServer
 
   // wait for connection to arrive, then display connection info
   private void waitForConnection() throws IOException
   {
      displayMessage( "Waiting for connection\n" );
      connection = server.accept(); // allow server to accept connection            
      displayMessage( "Connection " + counter + " received from: " +
         connection.getInetAddress().getHostName() );
   } // end method waitForConnection
 
   // get streams to send and receive data
   private void getStreams() throws IOException
   {
      // set up output stream for objects
      output = new ObjectOutputStream( connection.getOutputStream() );
      output.flush(); // flush output buffer to send header information
 
      // set up input stream for objects
      input = new ObjectInputStream( connection.getInputStream() );
 
      displayMessage( "\nGot I/O streams\n" );
   } // end method getStreams
 
   // process connection with client
   private void processConnection() throws IOException
   {
      String message = "Connection successful";
      sendData( message ); // send connection successful message
 
      // enable enterField so server user can send messages
      setTextFieldEditable( true );
 
      do // process messages sent from client
      { 
         try // read message and display it
         {
            message = ( String ) input.readObject(); // read new message
            displayMessage( "\n" + message ); // display message
         } // end try
         catch ( ClassNotFoundException classNotFoundException ) 
         {
            displayMessage( "\nUnknown object type received" );
         } // end catch
 
      } while ( !message.equals( "CLIENT>>> TERMINATE" ) );
   } // end method processConnection
 
   // close streams and socket
   private void closeConnection() 
   {
      displayMessage( "\nTerminating connection\n" );
      setTextFieldEditable( false ); // disable enterField
 
      try 
      {
         output.close(); // close output stream
         input.close(); // close input stream
         connection.close(); // close socket
      } // end try
      catch ( IOException ioException ) 
      {
         ioException.printStackTrace();
      } // end catch
   } // end method closeConnection
 
   // send message to client
   private void sendData( String message )
   {
      try // send object to client
      {
         output.writeObject( "SERVER>>> " + message );
         output.flush(); // flush output to client
         displayMessage( "\nSERVER>>> " + message );
      } // end try
      catch ( IOException ioException ) 
      {
         displayArea.append( "\nError writing object" );
      } // end catch
   } // end method sendData
 
   // manipulates displayArea in the event-dispatch thread
   private void displayMessage( final String messageToDisplay )
   {
      SwingUtilities.invokeLater(
         new Runnable() 
         {
            public void run() // updates displayArea
            {
               displayArea.append( messageToDisplay ); // append message
            } // end method run
         } // end anonymous inner class
      ); // end call to SwingUtilities.invokeLater
   } // end method displayMessage
 
   // manipulates enterField in the event-dispatch thread
   private void setTextFieldEditable( final boolean editable )
   {
      SwingUtilities.invokeLater(
         new Runnable()
         {
            public void run() // sets enterField's editability
            {
               enterField.setEditable( editable );
            } // end method run
         }  // end inner class
      ); // end call to SwingUtilities.invokeLater
   } // end method setTextFieldEditable
} // end class Server
 
Client class
// Fig. 27.7: Client.java
// Client portion of a stream-socket connection between client and server.
import java.io.EOFException;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.InetAddress;
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;
 
public class Client extends JFrame 
{
   private JTextField enterField; // enters information from user
   private JTextArea displayArea; // display information to user
   private ObjectOutputStream output; // output stream to server
   private ObjectInputStream input; // input stream from server
   private String message = ""; // message from server
   private String chatServer; // host server for this application
   private Socket client; // socket to communicate with server
 
   // initialize chatServer and set up GUI
   public Client( String host )
   {
      super( "Client" );
 
      chatServer = host; // set server to which this client connects
 
      enterField = new JTextField(); // create enterField
      enterField.setEditable( false );
      enterField.addActionListener(
         new ActionListener() 
         {
            // send message to server
            public void actionPerformed( ActionEvent event )
            {
               sendData( event.getActionCommand() );
               enterField.setText( "" );
            } // end method actionPerformed
         } // end anonymous inner class
      ); // end call to addActionListener
 
      add( enterField, BorderLayout.NORTH );
 
      displayArea = new JTextArea(); // create displayArea
      add( new JScrollPane( displayArea ), BorderLayout.CENTER );
 
      setSize( 300, 150 ); // set size of window
      setVisible( true ); // show window
   } // end Client constructor
 
   // connect to server and process messages from server
   public void runClient() 
   {
      try // connect to server, get streams, process connection
      {
         connectToServer(); // create a Socket to make connection
         getStreams(); // get the input and output streams
         processConnection(); // process connection
      } // end try
      catch ( EOFException eofException ) 
      {
         displayMessage( "\nClient terminated connection" );
      } // end catch
      catch ( IOException ioException ) 
      {
         ioException.printStackTrace();
      } // end catch
      finally 
      {
         closeConnection(); // close connection
      } // end finally
   } // end method runClient
 
   // connect to server
   private void connectToServer() throws IOException
   {      
      displayMessage( "Attempting connection\n" );
 
      // create Socket to make connection to server
      client = new Socket( InetAddress.getByName( chatServer ),12345);
 
      // display connection information
      displayMessage( "Connected to: " + 
         client.getInetAddress().getHostName() );
   } // end method connectToServer
 
   // get streams to send and receive data
   private void getStreams() throws IOException
   {
      // set up output stream for objects
      output = new ObjectOutputStream( client.getOutputStream() );      
      output.flush(); // flush output buffer to send header information
 
      // set up input stream for objects
      input = new ObjectInputStream( client.getInputStream() );
 
      displayMessage( "\nGot I/O streams\n" );
   } // end method getStreams
 
   // process connection with server
   private void processConnection() throws IOException
   {
      // enable enterField so client user can send messages
      setTextFieldEditable( true );
 
      do // process messages sent from server
      { 
         try // read message and display it
         {
            message = ( String ) input.readObject(); // read new message
            displayMessage( "\n" + message ); // display message
         } // end try
         catch ( ClassNotFoundException classNotFoundException ) 
         {
            displayMessage( "\nUnknown object type received" );
         } // end catch
 
      } while ( !message.equals( "SERVER>>> TERMINATE" ) );
   } // end method processConnection
 
   // close streams and socket
   private void closeConnection() 
   {
      displayMessage( "\nClosing connection" );
      setTextFieldEditable( false ); // disable enterField
 
      try 
      {
         output.close(); // close output stream
         input.close(); // close input stream
         client.close(); // close socket
      } // end try
      catch ( IOException ioException ) 
      {
         ioException.printStackTrace();
      } // end catch
   } // end method closeConnection
 
   // send message to server
   private void sendData( String message )
   {
      try // send object to server
      {
         output.writeObject( "CLIENT>>> " + message );
         output.flush(); // flush data to output
         displayMessage( "\nCLIENT>>> " + message );
      } // end try
      catch ( IOException ioException )
      {
         displayArea.append( "\nError writing object" );
      } // end catch
   } // end method sendData
 
   // manipulates displayArea in the event-dispatch thread
   private void displayMessage( final String messageToDisplay )
   {
      SwingUtilities.invokeLater(
         new Runnable()
         {
            public void run() // updates displayArea
            {
               displayArea.append( messageToDisplay );
            } // end method run
         }  // end anonymous inner class
      ); // end call to SwingUtilities.invokeLater
   } // end method displayMessage
 
   // manipulates enterField in the event-dispatch thread
   private void setTextFieldEditable( final boolean editable )
   {
      SwingUtilities.invokeLater(
         new Runnable() 
         {
            public void run() // sets enterField's editability
            {
               enterField.setEditable( editable );
            } // end method run
         } // end anonymous inner class
      ); // end call to SwingUtilities.invokeLater
   } // end method setTextFieldEditable
} // end class Client

Please edit your post and wrap your code with code tags:
[code=java]
<YOUR CODE HERE>
[/code]
to get highlighting and preserve formatting.

my code is giving this much trouble

Please explain. Copy the full contents of the console and paste it here.

why my code is giving this much trouble

Please explain what the problem is. What happens when you execute the code?

your not telling the server what its host IP is.. the port is set to 12345 which is sort of dramatic but should be fine for an example run / learning developer. However you will need to set the IP of the host also.

The server needs to know the IP that it is hosting look at this guide
ServerSocket (Java Platform SE 7 b123)

so

ServerSocket servSocket = new ServerSocket(12345, 100, "127.0.0.1");
-------

or specify the ip elsewhere however you should use localhost so it will allow the client to connect to the server. wan ip wont work unless you port forward which is another topic all together.

The client should then be set to connect to 127.0.0.1 (IP) and 12345 (PORT) which then should connect with no drama.

have you tried the server on another OS like WinXP to see if there is a problem with Win7?

Have you tried putting the server on WinXP?
I have my own HTTP server I use for testing. It is accessible when run on XP but not on Win7.

Can you explain where, how and in what order each program is being executed?

Then both programs were executed on the same PC which was using Win7.
Were the server and the client classes executed with their own JVM
or were they both executed in the same JVM from a third class that called their main() methods, server first and then client?

Ok. Thanks. I usually use a main() like this for testing client/server code in a single JVM:

   public static void main(String[] args) {
      Thread t1 = new Thread(new Runnable() {
         public void run() {
            try{new Server().runServer();}catch(Exception x){x.printStackTrace();}
         }
      });
      t1.start();
 
      try{Thread.sleep(100);}catch(Exception x){}  //  Let server start
 
      Thread t2 = new Thread(new Runnable() {
         public void run() {
            try{new Client("127.0.0.1").runClient();}catch(Exception x){x.printStackTrace();}
         }
      });
      t2.start();
 
 
      // wait and exit
      //  In case there is a infinite loop/bug that traps the GUI
      try{Thread.sleep(15000);}catch(Exception x){}
      System.out.println("Exiting main");
      System.exit(0);
 
   }