Java Chat Server takes up 100% of CPU w/ 2 cnxns? Please help me find whats wrong

[linksterman]

I am making this pretty basic chat project, and I found this echo server on the internet and decided to modify it my needs (much of the methods and fields are the same).

Basically what my program does is acts like a chat room. One computer runs the server which other java programs connect to and can communicate with one another. The problem is that this server I run is horribly inefficient.

I had to use 2 threads for each connection because one thread needs to continuously listen for incoming messages and the other has to send out messages for other computers. If i put them in the same thread the one that listens for messages will block the line for sending messages.

import java.net.*;
import java.io.*;
 
public class EchoServer
{        
    ServerSocket m_ServerSocket;
    private int counter=0;
    private String global_message = "first line";
 
    public EchoServer() 
    {
        try
        {
            m_ServerSocket = new ServerSocket(8008);
        }
        catch(IOException ioe)
        {
            System.out.println("Could not create server socket at 8008. Quitting.");
            System.exit(-1);
        }
 
        System.out.println("Port Created on 8008");
        int id = 0;
        while(true)
        {                        
            try
            {
                Socket clientSocket = m_ServerSocket.accept();
                ClientServiceThread cliThread = new ClientServiceThread(clientSocket, id++);
                ClientListner lisThread = new ClientListner(clientSocket, id++);
                cliThread.start();
                lisThread.start();
            }
            catch(IOException ioe)
            {
                System.out.println("Exception encountered on accept. Ignoring. Stack Trace :");
                ioe.printStackTrace();
            }
        }
    }
 
    public static void main (String[] args)
    {
        new EchoServer();    
    }
 
    class ClientListner extends Thread
    {
        Socket m_clientSocket;        
        int m_clientID = -1;
        boolean m_bRunThread = true;
 
        ClientListner(Socket s, int clientID)
        {
            m_clientSocket = s;
            m_clientID = clientID;
        }
 
        public void run()
        {            
            BufferedReader in = null; 
            PrintWriter out = null;
            PrintWriter tempout = null;
            System.out.println("Accepted Client : ID - " + m_clientID + " : Address - " + 
                             m_clientSocket.getInetAddress().getHostName());
 
            try
            {                                
                in = new BufferedReader(new InputStreamReader(m_clientSocket.getInputStream()));
                while(m_bRunThread)
                {                    
                    String tempitoo = in.readLine();
                    if (!(tempitoo==null))
                    {
                    global_message = tempitoo;
                       }
 
                    System.out.println("Client Says :" + global_message);
 
 
                    if(global_message.equalsIgnoreCase("close"))
                    {
                        m_bRunThread = false;   
                        System.out.print("Stopping client thread for client : " + m_clientID);
                    }
                    else
                    {}
                }
            }
            catch(Exception e)
            {
                e.printStackTrace();
            }
            finally
            {
                // Clean up
                try
                {                    
                    in.close();
                    out.close();
                    m_clientSocket.close();
                    System.out.println("...Stopped");
                }
                catch(IOException ioe)
                {
                    ioe.printStackTrace();
                }
            }
        }
    }    
    class ClientServiceThread extends Thread
    {
        Socket m_clientSocket;        
        int m_clientID = -1;
        boolean m_bRunThread = true;
 
        ClientServiceThread(Socket s, int clientID)
        {
            m_clientSocket = s;
            m_clientID = clientID;
        }
 
        public void run()
        {            
            BufferedReader in = null; 
            PrintWriter out = null;
            PrintWriter tempout = null;
            String clientCommand = "user: allo";
            try
            {                                
                out = new PrintWriter(new OutputStreamWriter(m_clientSocket.getOutputStream()));
                                            out.println("test");
                            out.flush();
 
                while(true)
                {              
 
                    if (!clientCommand.equals(global_message))
                    {
                            clientCommand = global_message;
                            out.println(global_message);
                            out.flush();
                            System.out.println("Message Sent");
 
                    }
                }
            }
            catch(Exception e)
            {
                e.printStackTrace();
            }
            finally
            {
                try
                {                    
                    in.close();
                    out.close();
                    m_clientSocket.close();
                    System.out.println("...Stopped");
                }
                catch(IOException ioe)
                {
                    ioe.printStackTrace();
                }
            }
        }
    }
} 

[linksterman]

I found out what is causing all my problems but I dont know how to fix it... it is in the ClientServiceThread Class of my code, where the while loop scans the global message continuously to see if it has changed.

Any ideas?