Build Jar file that download its dependencies automatically

Question

I am trying to build a Java project that I am going to eventually build into an executable Jar file. My Java project has some dependencies which are not packed inside my Jar file. So how can I make it so, so that when I run my jar file it will automatically download all the dependencies needed for it in order to run properly.

I dont want my jar file to be a fat jar file.

My Current build.gradle file looks like this:

/*
 * This file was generated by the Gradle 'init' task.
 *
 * This generated file contains a sample Java application project to get you started.
 * For more details take a look at the 'Building Java & JVM projects' chapter in the Gradle
 * User Manual available at https://docs.gradle.org/8.0.1/userguide/building_java_projects.html
 */



plugins {
    // Apply the application plugin to add support for building a CLI application in Java.
    id 'application'
}

repositories {
    // Use Maven Central for resolving dependencies.
    mavenCentral()
}

dependencies {
    // Use JUnit Jupiter for testing.
    testImplementation 'org.junit.jupiter:junit-jupiter:5.9.1'

    // This dependency is used by the application.
    implementation 'com.google.guava:guava:31.1-jre'
    implementation 'com.pi4j:pi4j-core:2.3.0'
    // implementation 'com.pi4j:pi4j-ktx:2.3.0' // Kotlin DSL
    implementation("com.pi4j:pi4j-plugin-raspberrypi:2.2.1")
    implementation("com.pi4j:pi4j-plugin-pigpio:2.2.1")
}

application {
    // Define the main class for the application.
    mainClass = 'new_folder.App'
}

jar {
    manifest {
        attributes 'Main-Class': application.mainClass
    }
}

tasks.named('test') {
    // Use JUnit Platform for unit tests.
    useJUnitPlatform()
}

Answer 1

you don't need to do anything.

gradle clean build

goto sub directory build/distributions

you can find DemoApp-1.0-SNAPSHOT.tar and DemoApp-1.0-SNAPSHOT.zip

unzip DemoApp-1.0-SNAPSHOT.tar

goto directory DemoApp-1.0-SNAPSHOT

goto bin, run command ./DemoApp

build.gradle

plugins {
    id 'java'
    id 'application'
}

group 'org.example'
version '1.0-SNAPSHOT'

repositories {
    mavenCentral()
}

dependencies {
    implementation 'com.google.guava:guava:31.1-jre'
    implementation 'com.pi4j:pi4j-core:2.3.0'
    implementation("com.pi4j:pi4j-plugin-raspberrypi:2.2.1")
    implementation("com.pi4j:pi4j-plugin-pigpio:2.2.1")
    
    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.1'
    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.1'
}

application {
    mainClass = 'org.example.Main'
}


test {
    useJUnitPlatform()
}

unzip DemoApp-1.0-SNAPSHOT.tar or DemoApp-1.0-SNAPSHOT.zip

File Structure

DemoApp-1.0-SNAPSHOT
├── bin
│   ├── DemoApp
│   └── DemoApp.bat
└── lib
    ├── checker-qual-3.12.0.jar
    ├── DemoApp-1.0-SNAPSHOT.jar
    ├── error_prone_annotations-2.11.0.jar
    ├── failureaccess-1.0.1.jar
    ├── guava-31.1-jre.jar
    ├── j2objc-annotations-1.3.jar
    ├── jsr305-3.0.2.jar
    ├── listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar
    ├── pi4j-core-2.3.0.jar
    ├── pi4j-library-pigpio-2.2.1.jar
    ├── pi4j-plugin-pigpio-2.2.1.jar
    ├── pi4j-plugin-raspberrypi-2.2.1.jar
    └── slf4j-api-1.7.32.jar

gradle application will create Run Script like DemoApp or DemoApp.bat

your dependencies implementation jar will put in lib.