//client.java

import java.net.*;
import java.io.*;

public class client {
    public static void main(String[] args) throws IOException{
        Socket s = new Socket("localhost", 4999);

        PrintWriter pr = new PrintWriter(s.getOutputStream());
        pr.println("is it working");
        pr.flush();

        InputStreamReader in = new InputStreamReader(s.getInputStream());
        BufferedReader bf = new BufferedReader(in);

        String str = bf.readLine();
        System.out.println("Server: "+str);
    }
}

//server.java
import java.net.*;
import java.io.*;

public class server {
    public static void main(String[] args) throws IOException{
        ServerSocket ss = new ServerSocket(4999);
        Socket s = ss.accept();

        System.out.println("Client Connected");

        InputStreamReader in = new InputStreamReader(s.getInputStream());
        BufferedReader bf = new BufferedReader(in);

        String str = bf.readLine();
        System.out.println("client: "+ str);

        PrintWriter pr = new PrintWriter(s.getOutputStream());
        pr.println("yes");
        pr.flush();
    }
}