JavaFX - Exception in Application start method?

Question

I am trying to create a JavaFX program, and every time I try to run my code I am getting an exception - I'm not entirely sure what it means though...

My code:

package application;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.stage.Stage;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.layout.BorderPane;


public class Main extends Application {
@Override
   public void start(Stage stage) throws Exception {
    Parent root = FXMLLoader.load(getClass().getResource("DogFinderFXML.fxml"));

    Scene scene = new Scene(root);

    stage.setScene(scene);
    stage.setTitle("HelloSwingNode Sample");
    stage.show();
}

/**
 * @param args the command line arguments
 */
public static void main(String[] args) {
    launch(args);
}

}

Stack trace:

Exception in Application start method
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 com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(Unknown Source)
    at com.sun.javafx.application.LauncherImpl.launchApplication(Unknown Source)
    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 sun.launcher.LauncherHelper$FXHelper.main(Unknown Source)
Caused by: java.lang.RuntimeException: Exception in Application start method
    at com.sun.javafx.application.LauncherImpl.launchApplication1(Unknown Source)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$147(Unknown Source)
    at com.sun.javafx.application.LauncherImpl$$Lambda$48/1732398722.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException: Location is required.
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.load(Unknown Source)
    at application.Main.start(Main.java:14)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$153(Unknown Source)
    at com.sun.javafx.application.LauncherImpl$$Lambda$51/1778973910.run(Unknown Source)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$166(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$$Lambda$44/1051754451.run(Unknown Source)
    at com.sun.javafx.application.PlatformImpl.lambda$null$164(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$$Lambda$47/813155481.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$165(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$$Lambda$46/1775282465.run(Unknown Source)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(Unknown Source)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$141(Unknown Source)
    at com.sun.glass.ui.win.WinApplication$$Lambda$37/1109371569.run(Unknown Source)
    ... 1 more
Exception running application application.Main

Any help will be appreciated,

Thanks

You must know how to read a StackTrace, it gives a good hint about where the problem is. Here, we see a `NullPointerException` occurring when you try openning a file, so the most probable cause of the error is that you gave a wrong path. When using the `Class.getResource` method, you must provide a local path from the location of the class on which is called the method. — Dici, Oct 19 '14 at 15:33
I fixed my same issue by remove the space of the sdk path name. — ybdesire, May 11 '20 at 09:17

score 14 · Answer 1 · edited May 15 '15 at 10:29

14

A simple fix: copy your fxml file/s into the package in which your main method is currently located. Save & re-run.

edited May 15 '15 at 10:29

BenRowley

24
7

answered Oct 19 '14 at 15:26

DeepInJava

1,871
3
16
31

or use relative path "../nameoffile.fxml". If the file is located one folder up. – Rengas May 05 '16 at 11:56
For me, it was that the app icon I was using was not in the correct place. placing the icon solved the issue. – ssi-anik Dec 15 '21 at 02:11

JavaFX - Exception in Application start method?

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