Gradle for Java 11 with Modules

Question

I'm trying to run a sample JavaFX app on Mac OS.

build.gradle

apply plugin: 'java'
apply plugin: 'application'

repositories {
    mavenCentral()
}


dependencies {
    compile "org.openjfx:javafx-base:11"
    compile "org.openjfx:javafx-graphics:11"
    compile "org.openjfx:javafx-controls:11"
}

compileJava {
    doFirst {
        println "CLASSPATH IS $classpath.asPath"
        options.compilerArgs = [
                '--module-path', classpath.asPath,
                '--add-modules', 'javafx.graphics'
        ]
        classpath = files()
    }
}

Java class

package com.test;

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.stage.Stage;


public class HelloFX extends Application {

    @Override
    public void start(Stage stage) {
        String javaVersion = System.getProperty("java.version");
        String javafxVersion = System.getProperty("javafx.version");
        Label l = new Label("Hello, JavaFX " + javafxVersion + ", running on Java " + javaVersion + ".");
        Scene scene = new Scene(l, 640, 480);
        stage.setScene(scene);
        stage.show();
    }

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

}

I use Gradle 4.10.2

Executing task 'gradle compileJava' I'm getting this error:

> Task :compileJava FAILED
CLASSPATH IS /Users/dragos.pruteanu/.gradle/caches/modules-2/files-2.1/org.openjfx/javafx-controls/11/58d961774262ec972bf304e16c154a8e18c2050b/javafx-controls-11.jar:/Users/dragos.pruteanu/.gradle/caches/modules-2/files-2.1/org.openjfx/javafx-graphics/11/a736dd079047ec0b72b8c4970842a5c5e0c19f2f/javafx-graphics-11.jar:/Users/dragos.pruteanu/.gradle/caches/modules-2/files-2.1/org.openjfx/javafx-base/11/9fcd3e8e3227ec97bf503f7991fad1f3b14d005/javafx-base-11.jar
error: module not found: javafx.graphics
1 error

What is wrong? For some reason the JavaFX libraries are not loaded correctly. Could be the error from MacOS or OpenJFX?

Since you're using Gradle, you need to take a look at the [Getting Started with JavaFX 11](https://openjfx.io/openjfx-docs/#gradle) article for Gradle specifically. Some special things must be done when adding the JavaFX modules in the `dependencies`. — Slaw, Nov 05 '18 at 07:03

Naman · Answer 1 · 2018-11-05T10:11:53.460

3

The reason why it would fail for you is mostly that the automatic module name derived out of the jar that you've used would not be javafx.graphics. Trying to get the details using the command line, I could observe the following:

jar --file=.../org/openjfx/javafx-graphics/11/javafx-graphics-11.jar --describe-module
No module descriptor found. Derived automatic module.

javafx.graphicsEmpty@11 automatic
requires java.base mandated

and since the module name resolved is not same as what you've specified in the command line --add-modules javafx.graphics, hence you're facing the stated error.

Additionally, one of the notes from Run HelloWorld using JavaFX 11 reads:

there is no need to add javafx.graphics module, since it is transitively required by the javafx.controls module

Edit from comments:- Steps defined at Run HelloWorld using Gradle with JavaFX would be a better place to look for appropriate steps to build with gradle.

As it states(edits mine), one needs to specify the platform in dependencies for e.g.

compile "org.openjfx:javafx-graphics:11:$platform"

... classifiers are not taken into account when resolving transitive dependencies in Gradle. Therefore, we need to specify ... modules with platform as classifier

and for which you might need the build script used in the sample as well to specify the platform/OS as a classifier.

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath 'com.google.gradle:osdetector-gradle-plugin:1.6.0'
    }
}

apply plugin: 'application'
apply plugin: 'com.google.osdetector'

ext.platform = osdetector.os == 'osx' ? 'mac' : osdetector.os == 'windows' ? 'win' : osdetector.os

edited Nov 05 '18 at 10:11

answered Nov 05 '18 at 05:52

Naman

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Thank you. But now if I remove the javafx.graphics I got : error: module not found: javafx.controls. Probably it has the same issue, with automatic module. How may I get my code compiled ? Won't this automatic modules bring a mess in javafx ? And one question about the HelloWorld article: why do they use OS specific jars ? Is really a distinct distribution for each OS ? – DbSchema Nov 05 '18 at 07:03
3

You may want to mention what's said in [Run HelloWorld using Gradle](https://openjfx.io/openjfx-docs/#gradle). One must include the platform classifier when declaring the JavaFX dependencies in Gradle. This also unfortunately means transitive dependencies aren't resolved (though that doesn't affect the `--add-modules` command). – Slaw Nov 05 '18 at 07:06
@dprutean There's OS specific distributions because the native code is unique to each OS. – Slaw Nov 05 '18 at 07:06
1

@Slaw Ya, ofcourse the link from Gradle would be good to share. I just wanted to point out the dependency clause, in general, to make the OP aware of the correct usage of `--add-modules` command. – Naman Nov 05 '18 at 10:03
Thank you for help. The sample from HelloWorld article works fine. Now I have one more question: if I have few jars stored in a lib folder, which is the correct way to include them ? I tried using this: dependencies { compile fileTree(dir: 'src/main/lib', include: ['*.jar']) but it does not work. – DbSchema Nov 05 '18 at 18:05
@dprutean I'm not very good at gradle though, but the way [you've specified the *libs* folder](https://stackoverflow.com/questions/20700053/how-to-add-local-jar-file-dependency-to-build-gradle-file) looks fine to me. Maybe if it doesn't work you can open another SO thread *with the details* and not extend this one. – Naman Nov 06 '18 at 01:14
1

I created a separate thread for the last question: https://stackoverflow.com/questions/53164973/gradle-migration-to-java-11 – DbSchema Nov 06 '18 at 05:23

Gradle for Java 11 with Modules

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