gradle

Gradle Best Practices

This guide outlines the definitive best practices for building robust, maintainable, and performant Java and Android projects with Gradle, leveraging the Kotlin DSL and modern features.

1. Adopt Kotlin DSL for Build Scripts

Always use the Kotlin DSL (build.gradle.kts) for new projects and when refactoring existing Groovy DSL (build.gradle) scripts. It offers strict typing, superior IDE support, and a unified language stack for Kotlin projects.

❌ BAD: Groovy DSL

// build.gradle
plugins {
    id 'java-library'
}
dependencies {
    implementation 'com.google.guava:guava:31.1-jre'
}

✅ GOOD: Kotlin DSL

// build.gradle.kts
plugins {
    `java-library`
}
dependencies {
    implementation("com.google.guava:guava:31.1-jre")
}

2. Modularize Your Build Early and Aggressively

Split your codebase into small, logical Gradle projects (modules) from the start. This is critical for leveraging Gradle's work avoidance, parallel execution, and minimizing compilation classpaths.

❌ BAD: Monolithic app module

├── app
│   ├── build.gradle.kts
│   └── src/main/java/org/example/... (all code here)
└── settings.gradle.kts
    include("app")

✅ GOOD: Modularized structure

├── app
│   └── build.gradle.kts
├── features/feature-a
│   └── build.gradle.kts
├── core/domain
│   └── build.gradle.kts
└── settings.gradle.kts
    include("app", "features:feature-a", "core:domain")

• Guideline: Each module should have a clear, single responsibility (e.g., api, implementation, feature, ui, core).

3. Centralize Dependencies with Version Catalogs

Manage all library versions in a single gradle/libs.versions.toml file. This eliminates duplication, simplifies upgrades, and ensures consistency across modules.

❌ BAD: Scattered versions or ext properties

// build.gradle.kts (multiple files)
val guavaVersion = "31.1-jre" // Or hardcoded
dependencies {
    implementation("com.google.guava:guava:$guavaVersion")
}