Dependency Management in Gradle

Introduction

Gradle resolves libraries from repositories into a local cache and wires them onto compile and runtime classpaths. You declare coordinates in dependencies { } using configurations such as implementation and testImplementation. This chapter adds Gson, compares configurations to Maven scopes, and shows how to inspect trees and fix conflicts.

Prerequisites

• Build script basics
• A project with java plugin and mavenCentral() repository

Add Gson and Parse JSON

Find coordinates on Maven Central — Gson example:

build.gradle:

dependencies {
    implementation 'com.google.code.gson:gson:2.11.0'
    testImplementation 'org.junit.jupiter:junit-jupiter:5.10.2'
}

Sync or build:

./gradlew build

src/main/java/com/example/JsonDemo.java:

Run with application plugin pointing at JsonDemo, or temporarily set mainClass in build.gradle.

Configurations vs Maven Scopes

dependencies {
    implementation 'com.google.code.gson:gson:2.11.0'
    compileOnly 'org.projectlombok:lombok:1.18.34'
    testImplementation 'org.junit.jupiter:junit-jupiter:5.10.2'
}

Version Catalog (libs.versions.toml)

Gradle 7+ supports a catalog under gradle/libs.versions.toml:

[versions]
gson = "2.11.0"
junit = "5.10.2"
 
[libraries]
gson = { group = "com.google.code.gson", name = "gson", version.ref = "gson" }
junit-jupiter = { group = "org.junit.jupiter", name = "junit-jupiter", version.ref = "junit" }

build.gradle:

dependencies {
    implementation libs.gson
    testImplementation libs.junit.jupiter
}

One file to bump versions across modules—common in Spring Boot 3+ templates.

BOM / Platform Alignment

Import a BOM to align versions (Spring, Jackson, etc.):

dependencies {
    implementation platform('org.springframework.boot:spring-boot-dependencies:3.4.0')
    implementation 'org.springframework.boot:spring-boot-starter-web'
}

Gradle respects BOM constraints when resolving versions.

Inspect the Dependency Tree

# Full runtime classpath tree
./gradlew dependencies --configuration runtimeClasspath
 
# Compile classpath
./gradlew dependencies --configuration compileClasspath

Find why a library appeared:

./gradlew dependencyInsight --dependency gson --configuration compileClasspath

Exclude Transitive Dependencies

dependencies {
    implementation('some.group:some-lib:1.0') {
        exclude group: 'commons-logging', module: 'commons-logging'
    }
}

Use when a transitive JAR causes conflicts or duplicate APIs.

Force a Version (Use Sparingly)

configurations.all {
    resolutionStrategy.force 'com.google.code.gson:gson:2.11.0'
}

Prefer BOMs or fixing the dependency that pulls the wrong version.

Reuse Maven Local Cache

If you already use Maven:

repositories {
    mavenLocal()
    mavenCentral()
}

Or global ~/.gradle/init.gradle as in IntelliJ chapter.

FAQ

Where are JARs stored?

~/.gradle/caches/modules-2/files-2.1/ (not the same path as ~/.m2 unless you use mavenLocal()).

implementation vs api?

implementation hides transitive deps from your library’s consumers; api exposes them.

Reload after editing build.gradle?

Run ./gradlew build or Reload Gradle in IDEA.

What comes next?

Gradle tasks.