NullPointerException and Resource directory in JavaFX and Gradle (distributed via a jar file)

Question

I am building a JavaFX application that is produced in Gradle to learn more about the process of building GUI applications in Java. A bump in the road that I have encountered involves accessing a .mp4 file to be displayed in the Media View. The intention is for this app to run through a .jar file, which I have been able to get to work with JavaFX 12 in general aside from the file reference hiccup.

I have referenced this Stack Overflow post and its solution still returns a Null Pointer in my project. Using

Paths.get("src/main/resources/hellofx/Blend_W-gladRLvno7U.mp4").toUri().toString();

does work, but will then yield a Media Exception in the jar format.

The file Structure is as follows:

.
build.gradle
src
|─── main
     |───java
         |───hellofx
             |─── HelloFX.java
             |─── Launcher.java
     |─── resources
          |─── hellofx
               |─── video.mp4

The gradle build file is:

plugins {
    id 'application'
    id 'org.openjfx.javafxplugin' version '0.0.7'
}

repositories {
    mavenCentral()
}

sourceSets {
    main {
        resources {
            srcDirs = ["src/main/resources"]
            includes = ["**/*.mp4"]
        }
    }
}

dependencies {
    /* uncomment for cross-platform jar: */
    runtimeOnly "org.openjfx:javafx-graphics:$javafx.version:win"
//    runtimeOnly "org.openjfx:javafx-graphics:$javafx.version:linux"
//    runtimeOnly "org.openjfx:javafx-graphics:$javafx.version:mac"
}

javafx {
    version = "12.0.1"
    modules = [ 'javafx.controls','javafx.fxml','javafx.media' ]
}

mainClassName = 'hellofx.HelloFX'

jar {
    manifest {
        attributes 'Main-Class': 'hellofx.Launcher'
    }
    from {
        configurations.runtimeClasspath.collect { it.isDirectory() ? it : zipTree(it) }
    }
}

And the Java Code is:

 public void start(Stage stage) {
        //Parent root = FXMLLoader.load(getClass().getResource("scene.fxml"));

        // Create and set the Scene.
        Scene scene = new Scene(new Group(), 640, 360);
        stage.setScene(scene);

//Returns Null Here (resource)
        final URL resource = HelloFX.class.getResource("imgs/Blend_W-gladRLvno7U.mp4");
//Returns Null here (loc)
        URL loc = this.getClass().getClassLoader().getResource("boop.txt");
        System.out.println(loc);

        String test = Paths.get("src/main/resources/hellofx/Blend_W-gladRLvno7U.mp4").toUri().toString();
        System.out.println(test);
        //Set up Media
        Media media = new Media(test);
        // Create the player and set to play automatically.
        MediaPlayer mediaPlayer = new MediaPlayer(media);
        mediaPlayer.setAutoPlay(true);

        // Create the view and add it to the Scene.
        MediaView mediaView = new MediaView(mediaPlayer);
        ((Group) scene.getRoot()).getChildren().add(mediaView);


        stage.setTitle("JavaFX and Gradle");
        stage.setScene(scene);
        stage.show();
    }

I have made an adjustment that did work in the end for me. I used the `Paths()` method as mentioned above, but using the full path towards that file as defined in my computer as opposed to the relative path in the project. Ie. `Paths.get("C:\\Users\\Me\\Folder\\Project\\src\\main\\resources\\hellofx\\Blend_W-gladRLvno7U.mp4").toUri().toString();` — Zac Bilmen, May 27 '19 at 19:42

Zubty · Accepted Answer · 2019-05-28T04:00:12.907

0

There is a simple explanation for that. You are trying to resolve a path but this is kind of complicated if it is pact into an jar file.

So if you want to get your mp4 file inside the jar do it similar to your boop.txt or Blend_W-gladRLvno7U.mp4 where you are getting it from your resources which will also work inside an packed jar.

So basically something like this:

this.getClass().getClassLoader().getResource("/hellofx/Blend_W-gladRLvno7U.mp4");

this should do the trick :)

edited May 28 '19 at 04:00

answered May 27 '19 at 07:20

Zubty

369
2
18

Thank you for the assistance, although your suggestion didn't seem to work for me. I am still receiving a null return upon putting the full relative path to the video file like you have shown above. I have also done another test where I put the video in the same directory as src and run the above method without trailing file path, and even that does not work. – Zac Bilmen May 27 '19 at 17:01
Sry i am changing the path i didn't do it correctly it should be this.getClass().getClassLoader().getResource("/hellofx/Blend_W-gladRLvno7U.mp4"); – Zubty May 28 '19 at 03:59
Thank you for the amendment. I tried it out, and it is still returning a NullPointerException. Do you think there may be something wrong outside of this problem to cause this? – Zac Bilmen May 29 '19 at 01:34
did you check if the mp4 is actually inside your jar file? Just for making sure – Zubty May 29 '19 at 04:21

NullPointerException and Resource directory in JavaFX and Gradle (distributed via a jar file)

1 Answers1