Java Runnable jar with imageview doesn't show GUI

Question

I am trying to make my project a runnable jar but the problem is that the gui is not showing up. From the error in my cmd i tell it is something about my imageviews.

My project contains imageviews which are located in another folder than the sourcefoler. I have set the buildpath, but it still doesn't seem to work

This is where I add the images to the GUI:

String path = "./imageTest/";
        File folder = new File(path);
        File[] listOfFiles = folder.listFiles();
        for (File file : listOfFiles) { <----- Line 51
            ImageView imageView;
            imageView = createImageView(file);
            tile.getChildren().addAll(imageView);
        }

The folder imageTest is added as a sourcefolder in the buildpath

This is the error I get when running the jar through cmd:

"Exception in Application start method
Exception in thread "main" java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoader.java:58)
Caused by: java.lang.RuntimeException: Exception in Application start method
        at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
        at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$155(LauncherImpl.java:182)
        at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException
        at application.guifx.MainScreen.mainScene(MainScreen.java:51)
        at application.guifx.MainApp.start(MainApp.java:37)
        at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863)
        at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)
        at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
        at java.security.AccessController.doPrivileged(Native Method)
        at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
        at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
        at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
        at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
        ... 1 more"

This is the MainApp

public class MainApp extends Application {
    private Service service;
    private Stage stage;
    private ScrollPane root = new ScrollPane();

    private MainScreen mainScreen; 

    public MainApp() {
        service = Service.getService();
        StorageInitializer.initStorage();

    }

    @Override
    public void start(Stage primaryStage) throws Exception {
        service = Service.getService();

        stage = primaryStage;

        mainScreen = new MainScreen(stage);

        stage.setWidth(100);
        stage.setHeight(100);

        primaryStage.setWidth(1000);
        primaryStage.setHeight(850);

        Scene scene = mainScreen.mainScene();<----- Line 37

        primaryStage.setScene(scene);
        primaryStage.show();
    }

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

    }

}

To be clear... The program works when laucnhing through eclipse, but doesn't when I make it a runnable jar This is how the system looks when opening it from eclipse Link

Possible duplicate of [What is a NullPointerException, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it) — Seelenvirtuose, Apr 16 '17 at 17:40

score 1 · Answer 1 · answered Apr 16 '17 at 17:45

1

Your variable listOfFiles is null. See : https://docs.oracle.com/javase/8/docs/api/java/io/File.html#listFiles--

Returns null if this abstract pathname does not denote a directory, or if an I/O error occurs.

Check if the variable path is initialized with an existing directory.
Check if your executable have rights to read the directory.
Check if the directory contains files

answered Apr 16 '17 at 17:45

cactuschibre

1,908
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I agree that the it must be because the listOfFiles is null, and that will mean that the build path to the folder imageTest doesn't work. So how do I do that correctly? My eclipse seems to find the way easily – Mads Stoltenborg Apr 16 '17 at 17:51
You can read this post to learn differents methods to load your resources : http://stackoverflow.com/questions/676250/different-ways-of-loading-a-file-as-an-inputstream – cactuschibre Apr 16 '17 at 17:54

Java Runnable jar with imageview doesn't show GUI

1 Answers1