Thread: CCN(Computer Communication and Network Systems)

Hi I have some knowledge about programming in general. However, it's my first time in programming in trying to communicate from one machine to another and I find it rather exiting. I have managed to communicate using a "Server.java" and "Client.java" class successfully by transmitting messages to a single server. My next task would be to create a buffer (string array) on server side and the next part is important "after sending 10 messages from "Client", "Server" should print a message "BUFFER FULL"." following are my two similar classes, and cannot wait to see this working, can somebody please help me? :-):

import java.io.*; 
import java.net.*; 
 
public class TCPMultiThreadServer { 
 
 
private static ServerSocket welcomeSocket;
 
private static final int PORT = 1234;
private static int clientNo =1;
  public static void main(String argv[]) throws Exception 
    { 
 
 
     System.out.println("Opening port...\n");
 
     try
		{
           welcomeSocket = new ServerSocket(PORT); 
 
 
}
		catch (IOException e)
		{}
 
 
 
     do { 
 
            Socket client = welcomeSocket.accept();
            System.out.println("\nNew client accepted.\n");
 
            //Create a thread to handle communication with
	    //this client and pass the constructor for this
	    //thread a reference to the relevant socket...
 
            TCPMultiThreadServer.ClientHandler handler = 
                new TCPMultiThreadServer().new ClientHandler(client,clientNo);
 
            handler.start(); //this method calls run.
 
 
		clientNo++; 
 
	 }while (true);
    }
 
 
 
class ClientHandler extends Thread
{
	private Socket client;
	private BufferedReader inFromClient;
        private BufferedReader text_to_Client;
 
	private DataOutputStream outToClient;
	public int clientNo;
 
       public boolean stopping; 
	public ClientHandler(Socket socket, int clientNos)
	{
		//Set up reference to associated socket...
		client = socket;
		clientNo= clientNos;
 
		try
		{
			inFromClient = 
              new BufferedReader(new
                  InputStreamReader(client.getInputStream()));
              text_to_Client =
              new BufferedReader(new InputStreamReader(System.in));
 
 
            outToClient = 
              new DataOutputStream(client.getOutputStream()); 
		}
		catch(IOException e)
		{}
	}
 
	public void run()
	{
 
		try
		{
 
    stopping = false;
		     String clientSentence; 
                     String capitalizedSentence;
                     Thread mythread = Thread.currentThread(); 
 
 
 do
 {
 
       //Accept message from client on
	   //the socket's input stream...
 
        OutputStream sout = client.getOutputStream();
 		// Just converting them to different streams, so that string handling becomes easier.
 
 
    	DataOutputStream text_to_send = new DataOutputStream(sout);
 
               clientSentence = inFromClient.readLine();
               System.out.println("Message received from client number " + clientNo + ": "+ clientSentence);
               System.out.println("Enter Message: ");
               clientSentence = text_to_Client.readLine();
               //capitalizedSentence = clientSentence.toUpperCase() + '\n';
               //int charCount = clientSentence.length();
               text_to_send.writeUTF(clientSentence);
               System.out.println("Your message: " + clientSentence);
               //outToClient.write(charCount);
 
         // System.out.println("\nlength: " + charCount);
 
          if (mythread.activeCount() == 2 && (clientNo ==0 || clientNo >0)  && clientSentence.equals("E"))
                 System.exit(0);
 
       } while(!clientSentence.equals("E"));
 
 
        client.close();
         } catch(IOException e)
  {} 
 
    } 
} 
}
 
 
import java.io.*; 
import java.net.*; 
class TCPClient1 { 
 
    public static void main(String argv[]) throws Exception 
    { 
        String sentence; 
        String modifiedSentence; 
 
        BufferedReader inFromUser = 
          new BufferedReader(new InputStreamReader(System.in)); 
 
        Socket clientSocket = new Socket("localhost",1234);
 
        DataOutputStream outToServer = 
          new DataOutputStream(clientSocket.getOutputStream()); 
 
       InputStream sin = clientSocket.getInputStream();
 
 
 			// Just converting them to different streams, so that string handling becomes easier.
			DataInputStream inFromServer = new DataInputStream(sin);
 
try{
 
  do  {
 
       System.out.print("Enter message: ");
        sentence = inFromUser.readLine(); 
 
        outToServer.writeBytes(sentence + '\n'); 
        System.out.print("Message sent! please wait for server message");
        modifiedSentence = inFromServer.readUTF();
 
        System.out.println("FROM SERVER: " + modifiedSentence); 
 
        } while(!sentence.equals("CLOSE"));      
  } catch(IOException e)
  {} 
        clientSocket.close();    
    } 
}

Hi there, when the first class "TCPMultiThreadServer" is ran, it prints:

TCPMultiThreadServer:
"run:
Opening port..."

I am then expected to run "TCPClient1" and that prints:

TCPClient1
run:
Enter message: hi
Message sent! please wait for server message "(I hit enter)

the messages are exchanged between the two classes:

TCPMultiThreadServer:
"
run:
Opening port...


New client accepted.

Message received from client number 1: hi
Enter Message:
"

How would you call back to the printStackTrace(), sorry I understand what you mean but can't seem to do it. Can I see the syntax if possible? It's just that mines still on infinite no of messages lol :-) Thanks.