导出为Runnable Jar文件，java执行错误

Question

Working with my project, which is done already, want it to compile and run from a single .jar file, as other mentioned that I should be using Export -> Runnable Jar file.

I select my main Server class, also selecting "Package required libraries into generated JAR" and pressing Finish.

Now I got a file named : Server.jar

Trying to run from console : java -jar Server.jar and getting error:

java.lang.NullPointerException
at server.Server.main(Server.java:34)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoader.java:58)

which refers to :

Socket socket = serverSocket.accept();

MANIFEST.MF File (Created auto):

Manifest-Version: 1.0
Rsrc-Class-Path: ./ json-simple.jar mysql-connector-java-5.1.42-bin.ja
 r
Class-Path: .
Rsrc-Main-Class: server.Server
Main-Class: org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader

I'm tired of guessing the problems, I'm new in Java, first doing the compiling. Any help?

My Server.java class :

package server;

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

import org.json.simple.parser.*;


public class Server {

    public static void main(String args[]) throws ParseException{

        ServerSocket serverSocket = null;
        ArrayList<ClientComm> clients = new ArrayList<ClientComm>();

        try{
                new Config();
            serverSocket = new ServerSocket(Config.getPort()); // can also use static final PORT_NUM , when defined
            System.out.println("Server started");
            System.out.println("test");
        }
        catch(IOException e){
            e.printStackTrace();
            System.out.println("Server error");
        }

        int clientID = 0;

        while(true){
            try{
                    System.out.println("Waiting for new connection");
                Socket socket = serverSocket.accept();
                clientID++;
                System.out.println("New connection on socket: " + socket);
                ClientComm clientComm = new ClientComm(socket, clientID);
                clients.add(clientComm);

                if(clientComm.checkAuth() == false) {
                        System.out.println("Client was dropped from connection because auth codes did not match");
                        socket.close();
                }
                else {
                        clientComm.start();
                }  
            }
            catch(Exception e){
                e.printStackTrace();
                System.out.println("Connection Error");
            }
        }

    }

}

Answer 1

The problem was solved long time ago. Was my personal bad with lack of experience in programming with java.