StringServer.java

import java.io.IOException;
import java.net.URI;
import java.util.List;
import java.util.ArrayList;


class Handler implements URLHandler {
    // The one bit of state on the server: a number that will be manipulated by
    // various requests.
    List <String> list = new ArrayList<String>();

    public String handleRequest(URI url) {
        if (url.getPath().equals("/")) {
            return toListS();
        } 
        else if (url.getPath().equals("/add-message")) {

            if (url.getPath().contains("/add-message")) {
                String[] parameters = url.getQuery().split("=");
                if (parameters[0].equals("s")) {
                    list.add(parameters[1]);
                    return toListS();
                }
            }
        } 
        
        return "404 Not Found!";
    }

    public String toListS() {
        String ret = "";
        for (int i = 0; i < list.size(); i++) {
            ret = ret + list.get(i) + "\n";
        }
        return ret;
    }
}

class StringServer {
    public static void main(String[] args) throws IOException {
        if(args.length == 0){
            System.out.println("Missing port number! Try any number between 1024 to 49151");
            return;
        }

        int port = Integer.parseInt(args[0]);

        Server.start(port, new Handler());
    }
}