ServerSocket.accept（）中的应用程序块

Question

I'm trying to realize a simple client/server application in Java8. I'm using this code:

`package prova;

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;



public class Main {
    public static void main(String args[]){
        ServerSocket ssock;
        try {
            System.out.println("Listening");
            ssock = new ServerSocket(8080);
            while(true){
                Socket sock;
                try {
                    sock = ssock.accept();
                    System.out.println("Connected");
                    new Thread(new Server(sock)).start();
                }catch(IOException e1){e1.printStackTrace();}
            }
        }catch(IOException e2){e2.printStackTrace();}
    }
}`

Server.java

package prova;

import java.io.IOException;
import java.io.PrintStream;
import java.net.Socket;

public class Server implements Runnable{

    Socket clientSocket;

    public Server(Socket cSocket){
        this.clientSocket = cSocket;
    }

    public void run(){
         try {
             PrintStream pstream = new PrintStream
             (clientSocket.getOutputStream());
             for (int i = 100; i >= 0; i--) {
                pstream.println(i + 
                " bottles of beer on the wall");
             }
             pstream.close();
             clientSocket.close();
          }
          catch (IOException e) {
             System.out.println(e);
          }
    }

}

When the application arrives to execute the instruction ssock.accept(); the application crashes. I really don't know what's the matter with this code. I've searched on internet but except for class server there is no difference between my code and a lot of solution/examples that i found. By the way since the application doesn't arrive to execute the thread I guess this is not related to my issue, maybe I'm wrong. Thank you all in advance

Answer 1

that's the strange fact it doesn't provide any stacktrace. I'm running this code on win10 with eclipse mars 4.5.2. the code stops at this instruction sock = ssock.accept();

Yes, it's supposed to stop there -- it's waiting for a client program to connect on that same socket, server socket 8080, that's what accept() does, but you don't do that anywhere. The fix is simple -- have your client try to connect on the same socket that the server is waiting on.