I'm working on a Java 17 project using Gradle with the Java module system, and I'm encountering an issue when trying to include the Apache Commons Math (commons-math3) library in my project.

What I am trying to do: I have a 'module-info.java' file where I'm trying to add the following dependencies:

java
module com.example {
    requires org.apache.pdfbox;
    requires org.apache.poi.ooxml;
    requires commons.math3;
    requires org.apache.commons.collections4;
    exports org.example;
    }

In my build.gradle, I have the following dependencies declared:

dependencies {
        implementation 'org.apache.pdfbox:pdfbox:2.0.30'
        implementation 'org.apache.poi:poi-ooxml:5.3.0'
        implementation 'org.apache.commons:commons-math3:3.6'
    }

When I try to build the project using gradle build or run it via IntelliJ, I get the following error:

error: module not found: commons.math3
        requires commons.math3;

Checking if the dependency is downloaded correctly with gradlew dependencies.

module-info.java

• Change exports org.example; to exports com.example;.

module com.example {
    requires org.apache.pdfbox;
    requires org.apache.poi.ooxml;
    requires commons.math3;
    requires org.apache.commons.collections4;
    exports com.example;
    }

build.gradle

• Add the following content to the build.gradle file.

ext.moduleName = 'com.example'

tasks.compileJava {
    inputs.property('moduleName', moduleName)
    doFirst {
        options.compilerArgs = [
                '--module-path', classpath.asPath
        ]
        classpath = files()
    }
}

UPDATE

My test project

Project Tree

HelloMath
├── build.gradle
└── src
    └── main
        └── java
            ├── com
            │   └── example
            │       └── HelloMathApp.java
            └── module-info.java

build.gradle

plugins {
    id 'java'
    id 'application'
}
application {
    mainClass = 'com.example.HelloMathApp'
    //module
    //mainClass = 'com.example/com.example.HelloMathApp'
}

group = 'com.example'
version = '0.0.1-SNAPSHOT'
description = 'Hello Apache Commons Math App Project'

java {
    sourceCompatibility = JavaVersion.VERSION_17
    targetCompatibility = JavaVersion.VERSION_17
    modularity.inferModulePath = true
}

ext.moduleName = 'com.example'

tasks.compileJava {
    inputs.property('moduleName', moduleName)
    doFirst {
        options.compilerArgs = [
                '--module-path', classpath.asPath
        ]
        classpath = files()
    }
}

tasks.withType(JavaCompile) {
    options.encoding = 'UTF-8'
}


repositories {
    mavenCentral()
}

dependencies {
    // Apache Commons Math 4 Legacy
    //implementation 'org.apache.commons:commons-math4-legacy:4.0-beta1'
    // Apache Commons Math 3 
    implementation 'org.apache.commons:commons-math3:3.6.1'

}

tasks.jar {
    archiveBaseName = 'app'
}

tasks.register('copyDependencies', Copy) {
    def outputDir = layout.buildDirectory.dir('libs')
    from configurations.runtimeClasspath
    into outputDir
}

module-info.java

module com.example {
    requires commons.math3;
    requires java.base;
    exports com.example;
}

HelloMathApp.java

package com.example;

//org.apache.commons:commons-math3:3.6.1
import org.apache.commons.math3.analysis.function.Abs;

//org.apache.commons:commons-math4-legacy:4.0-beta1
//import org.apache.commons.math4.legacy.analysis.function.Abs;

public class HelloMathApp {

    public static void main(String... args) {
        Abs abs = new Abs();
        System.out.println(abs.value(-10.0d));
    }

} 

Open Terminal:

Gradle Run

gradle clean run

Output

> Task :run
10.0

Gradle Build

gradle clean build

HelloMath
├── build
│   ├── distributions <-- plugins 'application' 
│   │   ├── HelloMath-2-0.0.1-SNAPSHOT.tar
│   │   └── HelloMath-2-0.0.1-SNAPSHOT.zip
│   ├── libs
│   │   └── app-0.0.1-SNAPSHOT.jar

Gradle Download Dependencies

gradle copyDependencies

HelloMath
├── build
│   └── libs
│       ├── app-0.0.1-SNAPSHOT.jar
│       └── commons-math3-3.6.1.jar <-- Dependencies

Run with build/libs/ jars

java \
  -cp "build/libs/*" \
  com.example.HelloMathApp

Output

10.0

Run with application

• For Linux , use tar: HelloMath-xxx.tar
• For Windows , use zip: HelloMath-xxx.zip
• and version number 2-0.0.1, you must change to your number

build/distributions/HelloMath-2-0.0.1-SNAPSHOT.tar

Unpacking HelloMath-2-0.0.1-SNAPSHOT.tar

HelloMath/build/distributions/HelloMath-2-0.0.1-SNAPSHOT
├── bin
│   ├── HelloMath
│   └── HelloMath.bat
└── lib
    ├── app-0.0.1-SNAPSHOT.jar
    └── commons-math3-3.6.1.jar

Run - 1

cd build/distributions/HelloMath-2-0.0.1-SNAPSHOT/bin
./HelloMath

Output

10.0

HelloMath is generated by plugins application.

Run - 2

cd build/distributions/HelloMath-2-0.0.1-SNAPSHOT
java --module-path lib --module com.example/com.example.HelloMathApp

Output

10.0