Why does my program start in Eclipse but not as a jar file?

Question

first things first that need to be said: I am really new at java developement and also this is my first post on StackOverflow. So i would really appreciate, if you people could give me general tips if i am doing something wrong with this thread i am opening. Now i have never built an executable java project before and i tried building my first project with Eclipse. Somehow though, i get an error when starting the jar file which is as follows:

`java.lang.IllegalStateException: Location is not set.
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2434)
    at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2409)
    at application.Main.start(Main.java:46)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$161(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$174(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
    at java.lang.Thread.run(Unknown Source)`

And here is my class that causes the problem. I am sorry for any weird comments or println's i was trying to debug.

package application;

import java.util.ArrayList;
import java.util.HashMap;

import controller.SplendorController;
import controller.TurnController;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
import model.Bank;
import model.Card;
import model.Player;
import model.Resource;
import model.Tree;
import model.Turn;
import view.MainScreenController;

public class Main extends Application {
    @Override
    public void start(Stage primaryStage) {     

        try {
            System.out.println("test");
            SplendorController splendorC = new SplendorController();

        /*  ArrayList<Player> players = new ArrayList<>(); 
          players.add(new
          Player("Klaus", model.Mode.HUMAN)); players.add(new
              Player("Dieter", model.Mode.HUMAN)); 

          players.add(new
                  Player("Dieter2", model.Mode.HUMAN)); 
            Turn currentTurn =
              splendorC.getGameController().setUpGame(players);
              Tree<Turn> currentTurnTree = new Tree<Turn>(currentTurn);
              //System.out.println("Das ist der Baum : " + splendorC.getAIController().
              //generateTreeRecursiveUntilDepth(currentTurnTree, currentTurnTree, 2));
              long startTime = System.nanoTime();    
              System.out.println("Das ist der errechnete Zug" + splendorC.getAIController().turnHard());
              System.out.println((double)(System.nanoTime() - startTime)/ 1_000_000_000 + " seconds.");*/

            FXMLLoader loader = new FXMLLoader(getClass().getResource("../view/main1610.fxml"));
            BorderPane root = (BorderPane) loader.load();
            MainScreenController _MainScreenController = (MainScreenController) (loader.getController());
            _MainScreenController.setSpc(splendorC);
            splendorC.getIOController().save("./saved_games/game");

            // MainScreenController.setSplendidController(_SplendidController);

            // Application.setUserAgentStylesheet(Application.STYLESHEET_MODENA);
            // StyleManager.getInstance().addUserAgentStylesheet(getClass().getResource("application.css").toString());

            Scene scene = new Scene(root);
            // new JMetro(scene, Style.LIGHT);
            // scene.getStylesheets().add("./application/application.css");

            primaryStage.setScene(scene);
            primaryStage.setTitle("Splendid");
            primaryStage.setFullScreen(true);
            primaryStage.show();
            String uriString = new String(
                    getClass().getResource("/sounds/Ascence - About You [NCS Release].mp3").toURI().toString());

            /*
             * Media media = new Media(uriString); MediaPlayer player = new
             * MediaPlayer(media); MediaView mv = new MediaView(player);
             * root.getChildren().add(mv);
             * 
             * player.cycleCountProperty().set(MediaPlayer.INDEFINITE);
             * player.setVolume(0.30); player.play();
             */
            _MainScreenController.setSpc(splendorC);
            _MainScreenController.init(primaryStage);

            /*
             * SampleViewController sampleViewController = new
             * SampleViewController(); Scene scene = new
             * Scene(sampleViewController,400,200);
             * scene.getStylesheets().add(getClass().getResource(
             * "application.css").toExternalForm());
             * primaryStage.setScene(scene); primaryStage.show();
             */
        } catch (Exception e) {

            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        launch(args);
    }
}