[FIXED] Maven - JavaFX jar built with maven can't execute (`NoClassDefFoundError`)

Issue

I am trying to distribute a cross-platform JavaFX application (in jar format), so the user doesn't need to have access to their own JavaFX library in order to run the application. The best choice to do this is apparently using Maven.

As this is my first time using Maven, and I am not very familiar with how it works, I have encountered some problems even though I have followed various tutorials.

The following is my pom.xml for my project.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>MM</groupId>
    <artifactId>TP_2</artifactId>
    <packaging>jar</packaging>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>15</maven.compiler.source>
        <maven.compiler.target>15</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-fxml</artifactId>
            <version>16</version>
        </dependency>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-fxml</artifactId>
            <version>16</version>
            <classifier>win</classifier>
        </dependency>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-fxml</artifactId>
            <version>16</version>
            <classifier>mac</classifier>
        </dependency>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-fxml</artifactId>
            <version>16</version>
            <classifier>linux</classifier>
        </dependency>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-controls</artifactId>
            <version>16</version>
            <classifier>win</classifier>
        </dependency>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-controls</artifactId>
            <version>16</version>
            <classifier>linux</classifier>
        </dependency>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-controls</artifactId>
            <version>16</version>
            <classifier>mac</classifier>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <release>15</release>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.openjfx</groupId>
                <artifactId>javafx-maven-plugin</artifactId>
                <version>0.0.8</version>
                <configuration>
                    <mainClass>mvc.Launcher</mainClass>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <configuration>
                    <archive>
                        <manifestFile>src/main/java/META-INF/MANIFEST.MF</manifestFile>
                    </archive>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

When I build the project, everything seems fine. No error has been reported and the jar was created successfully. However, when I try to execute the jar (with java -jar command), I got the following exception.

Exception in thread "main" java.lang.NoClassDefFoundError: javafx/application/Application
    at java.base/java.lang.ClassLoader.defineClass1(Native Method)
    at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1010)
    at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:150)
    at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:855)
    at java.base/jdk.internal.loader.BuiltinClassLoader.findClassOnClassPathOrNull(BuiltinClassLoader.java:753)
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:676)
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:634)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:182)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:519)
    at mvc.Launcher.main(Launcher.java:5)
Caused by: java.lang.ClassNotFoundException: javafx.application.Application
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:636)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:182)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:519)
    ... 10 more

I am not really sure where is my problem with Maven? I have tried to clean and rebuild, but it still doesn't work.

For reference, I mainly followed the solution of this thread: https://stackoverflow.com/a/53536555/7036218

Solution

You don't have a problem with Maven. Your problem is what you are trying to do. Distributing JavaFX applications as fat jars is simply not very well supported. Have a look at JPackage instead. It comes with any recent JDK. And then maybe follow this tutorial: https://github.com/dlemmermann/JPackageScriptFX

Answered By - mipa
Answer Checked By - David Marino (JavaFixing Volunteer)