Question

Why does nothing get printed out to the console?

I have a server socket which starts a new thread for each client. It reads a line from the client outputs it and sends a response of its own. This is printed on the client side. Here’s the code:

The client code:

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;

public class Client {
    public static void main(String[] args) {
        PrintWriter out = null;
        BufferedReader in = null;
        Socket echoSocket=null;
        try {
            echoSocket = new Socket("localhost", 8999);
            out = new PrintWriter(echoSocket.getOutputStream(), true);
            in = new BufferedReader(new InputStreamReader(echoSocket.getInputStream()));
            for(int i=0;i<20;i++) {
                out.print("Sending to Server"+i);
                System.out.println("Received from Server"+in.readLine());
            }

        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            try {
                try {
                    in.close();
                } finally {
                    try {
                        out.close();
                    } finally {
                        echoSocket.close();
                    }
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
    }
}    

The server code:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.concurrent.Callable;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class Server {

    /**
     * @param args
     */
    public static void main(String[] args) {
        try {
            final ServerSocket server = new ServerSocket(8999);
            final ExecutorService threadPool = Executors.newFixedThreadPool(2);
            while (true) {
                try {
                    final Socket sock = server.accept();
                    threadPool.submit(new Callable<Void>() {
                        @Override
                        public Void call() throws Exception {
                            BufferedReader br = null;
                            PrintWriter out = null;
                            try {
                                br = new BufferedReader(new InputStreamReader(sock.getInputStream()));
                                out = new PrintWriter(sock.getOutputStream(), true);
                                for (int i = 0; i < 20; i++) {
                                    String readLine = br.readLine();
                                    System.out.println(readLine);
                                    out.print(readLine + "response");
                                }
                            } finally {
                                try {
                                    br.close();
                                } finally {
                                    try {
                                        out.close();
                                    } finally {
                                        sock.close();
                                    }
                                }
                            }
                            return null;
                        }
                    });
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

        } catch (IOException e) {
            e.printStackTrace();
        }

    }

}

Answer 1

Well for one, you should probably println instead of print on your writers (in both client and server).