Exception in thread "main" java.net.SocketException: Socket is closed
	at java.net.Socket.getInputStream(Socket.java:903)
	at client.Client.main(Client.java:38)
C:\Users\ok\AppData\Local\NetBeans\Cache\8.1\executor-snippets\run.xml:53: Java returned: 1
СБОРКА ЗАВЕРШЕНА СО СБОЕМ (общее время: 1 минута 3 секунды)

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.logging.Level;
import java.util.logging.Logger;


public class Server {
    
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(15123);
        
        while (true) {
            Socket socket = serverSocket.accept();
            Runnable r = new ThreadedEchoHandler(socket);
            Thread t = new Thread(r);
            t.start();
        }
    }
}

class ThreadedEchoHandler implements Runnable {
 
    Socket socket;
 
    public ThreadedEchoHandler(Socket socket) {
        this.socket = socket;
    }
 
    @Override
    public void run() {
 
        String FILE_NAME = "files/file1.txt";

        File transferFile = new File(FILE_NAME);

        try (FileInputStream in = new FileInputStream(transferFile);) {

            OutputStream out = socket.getOutputStream();

            int c = 0;
            while ((c = in.read()) >= 0) {
                out.write(c);
                out.flush();
            }
            
            out.close();
            in.close();
//        s.close();
//            socket.close();

            System.out.println("File transfer complete");
        } catch (IOException ex) {
            Logger.getLogger(ThreadedEchoHandler.class.getName()).log(Level.SEVERE, null, ex);
        }
        finally{
            if (socket != null) {
                try {
                    socket.close();
                } catch (IOException ex) {
                    Logger.getLogger(ThreadedEchoHandler.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        }
    }
}

import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

public class Client {
    
    public static void main(String[] args) throws UnknownHostException, IOException {
        
        Socket socket = new Socket(InetAddress.getLocalHost(), 15123);
        System.out.println("Accepted connection : " + socket);
 
        BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));
        
        String userInput;
        String FILE_NAME = "files/file1.txt";
        
        while ((userInput = stdIn.readLine()) != null) {

            if (userInput.toLowerCase().equals("exit")) {
                break;
            }

            if (userInput.equals("1")) {

                InputStream in = socket.getInputStream();

                File copyFileName = new File(FILE_NAME);
                FileOutputStream out = new FileOutputStream(copyFileName);

                int c = 0;
                while ((c = in.read()) >= 0) {
                    out.write((char) c);
                }
                out.close();
                in.close();
//                socket.close();
            }
        }

        socket.close();
    }
}