java.lang.reflect.InvocationTargetException in javafx program

Question

I am currently trying to code a simple MediaPlayer to explore javafx. (beginner here) I want to open a mp3 file and simply play it but when i launch it there is an exception ive never seen.

Heres the code:

@Override
public void start(Stage primaryStage) {
    Media pick = new Media("file:///" + System.getProperty("Benutzer.dir").replace('\\', '/') + "/" + "oof.mp3");
    MediaPlayer player = new MediaPlayer(pick);

    MediaView mediaView = new MediaView(player);

    Group root = new Group(mediaView);
    Scene scene = new Scene(root, 500, 200);

    primaryStage.setTitle("MediaPlayerTest");
    primaryStage.setScene(scene);
    primaryStage.show();

    player.play();
}

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

And the exception:

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(LauncherImpl.java:389)
    at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
    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$FXHelper.main(Unknown Source)
Caused by: java.lang.RuntimeException: Exception in Application start method
 at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$154(LauncherImpl.java:182)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException
 at soundEdit.start(soundEdit.java:13)
    at com.sun.javafx.application.LauncherImpl.lambda$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)

Already tried to find a solution but cant really find anything. Thanks for the help.

@fabian This question can't be considered a duplicate for the provided link, the problem is that he's incorrectly accessing the resources for his application, also he's not asking what's a null pointer exception he's asking how to solve the problem of accessing resources. — Bara' Hashesh, Sep 26 '18 at 13:05

score 0 · Answer 1 · answered Sep 26 '18 at 12:04

0

If you read the stack of error you will notice that the error is caused by a null pointer exception at line 13 of the code can you kindly highlight that line, not sure which one.

Also when getting resources it's best to use the getClass().getResourcesAsStream() or getClass().getResource() methods.

answered Sep 26 '18 at 12:04

Bara' Hashesh

129
7

Line 13 of the code is: Media pick = new Media("file:///" + System.getProperty("Benutzer.dir").replace('\\', '/') + "/" + "oof.mp3"); – ekelix Sep 26 '18 at 12:23
Can you try printing the result of System.getProperty("Benutzer.dir") – Bara' Hashesh Sep 26 '18 at 12:25
Says null when i print it – ekelix Sep 26 '18 at 12:30
That's the problem you try to use . replace () on a null value as such the null pointer exception – Bara' Hashesh Sep 26 '18 at 12:30
So where should i put the mp3 then and how can i use it in the project? – ekelix Sep 26 '18 at 12:34
Put the MP3 file under the src file and use the getClass().getResource() method, it returns the URL of the file and I think there is a .getFile() method under it – Bara' Hashesh Sep 26 '18 at 12:38
The get resource method takes the path to the file and always start with / which will refrence the src folder – Bara' Hashesh Sep 26 '18 at 12:39

java.lang.reflect.InvocationTargetException in javafx program

1 Answers1