How to send data in a java socket program without closing socket

i created a sever socket program to send a stream data to Apache spark.But data is received by spark after i close the socket or termination of program.i need to send data without closing socket and terminating program.

 import java.io.DataOutputStream;
 import java.net.ServerSocket;
 import java.net.Socket;
 import java.util.Scanner;

public class SocketServer {
public static void main(String[] args) {
    try {
        ServerSocket ss = new ServerSocket(9999);
        Socket s = ss.accept();// establishes connection

        DataOutputStream dout = new DataOutputStream(s.getOutputStream());
        Scanner scanner = new Scanner(System.in);
        String s1 = "";
        while (!s1.equals("end")) {
            s1 = scanner.next();
            dout.writeUTF(s1);
            dout.flush();
        }
     ss.close();
    } catch (Exception e) {r
        System.out.println(e);
    }
  }
}

i can send data in stream using nc server nc -lk 9999.

EDIT -1 Tried with println

try {
        ServerSocket ss = new ServerSocket(6000);
        Socket s = ss.accept();// establishes connection

        OutputStream ostream = s.getOutputStream();
        PrintWriter pwrite = new PrintWriter(ostream, true);
        Scanner scanner = new Scanner(System.in);
        String s1 = "";
        while (!s1.equals("end")) {
            s1 = scanner.next();
            pwrite.println(s1);
            pwrite.flush();
        }
        ss.close();
    } catch (Exception e) {
        System.out.println(e);
    }

Still not working.

Please help..

Copyright Notice：Content Author:「BlackPOP」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/28980604/how-to-send-data-in-a-java-socket-program-without-closing-socket