Socket Server with multiple client in java

Question

I have to create a socket server which will listen to multiple client. Suppose there are 6 clients connected to the server at the same time and each of the clients are sending s

Answer 1

Create a new thread per client connection and continually do a blocking read on the streams in each thread to look for data to process.

class Server {

    ClientThread    threads[];
    int             size;
    ServerSocket    serverSocket;
    boolean         active;

    Server() throws Exception {
        /* initialize connection */
        active = true;
        listen();
    }

    void listen() throws Exception {
        while ( active ) {
            Socket clientSocket = serverSocket.accept();
            threads[ size++ ] = new ClientThread( clientSocket );
            threads[ size - 1 ].start();
        }
    }
}

class ClientThread extends Thread {

    OutputStream    out;
    InputStream     in;
    boolean         active;

    ClientThread( Socket clientSocket ) throws Exception {
        out = clientSocket.getOutputStream();
        in = clientSocket.getInputStream();
    }

    public void run() {
        active = true;
        while ( active ) {
            listen();
        }
    }

    private void listen() {
        try {
            int res = process( in.read() );
            out.write( res );
        } catch ( Exception e ) {}
    }

    private int process( int b ) {
        return -1;
    }
}

Answer 2

Any reason you can't use a servlet container to do this? This is 10 lines of code in a Servlet + Tomcat/Jetty.