If you’ve worked on an Android project, you’ve definitely dealt with Gradle dependencies. They help bring in external libraries, connect different parts of your project, and even let you add custom files. But not all dependencies work the same way. Some are used for linking modules, others for adding external projects, and some for including specific files. Choosing the right type can make your project more organized and easier to maintain.

In this blog, we’ll break down the different types of Gradle dependencies and when to use each one.

Types of Gradle dependencies

Gradle provides three main types of dependencies: 

• Module dependencies
• Project dependencies
• File dependencies

Each type serves a different purpose, and choosing the right one ensures better project organization, maintainability, and performance.

Module Dependencies: The Standard Approach

Module dependencies are the most commonly used in Android development. They allow you to connect different modules within the same project.

Example use case:

• You have a core module that handles networking and database logic.
• Your app module depends on core to access those functionalities.

In Gradle, this might look like:

implementation project(":core")

Why use module dependencies?

• Encourages modularization, making projects easier to scale.
• Improves build times by allowing Gradle to compile modules separately.
• Keeps your code organized and avoids duplication.

Project Dependencies: Linking External Projects

Project dependencies come into play when you want to include another Gradle project that isn’t part of your main project by default.

Example use case:

• You’re working on a shared internal library that’s used across multiple apps.
• Instead of publishing it to Maven or JCenter every time, you directly link the project.

In Gradle:

implementation project(path: ':shared-library')

Why use project dependencies?

• Great for internal library development.
• Lets you work with multiple projects simultaneously without extra publishing steps.
• Useful in large teams or enterprise-level apps.

File Dependencies: Adding Custom JAR or AAR Files

File dependencies allow you to include JAR or AAR files directly into your project.

Example use case:

• You’re integrating a third-party SDK that isn’t available in a public Maven repository.
• You have a legacy .jar file you need for backward compatibility.

In Gradle:

implementation files('libs/custom-library.jar')

Why use file dependencies?

• Perfect for custom or private libraries.
• Helps when working with offline builds or older dependencies.

Best practice: Use file dependencies sparingly. If a library is available via Maven Central or Google’s repository, prefer that method — it’s easier to update and maintain.

Best Practices for Managing Gradle Dependencies

• Prefer remote repositories (Maven Central, Google) over file dependencies.
• Modularize your project: keep reusable logic in separate modules.
• Use version catalogs (Gradle 7+) to centralize dependency versions.
• Keep dependencies updated to avoid security vulnerabilities.
• Avoid duplication by consolidating commonly used libraries in shared modules.

Conclusion

Gradle dependencies may seem simple, but choosing the right type — module, project, or file — can have a huge impact on your Android project’s structure and maintainability.

• Use module dependencies for modular apps.
• Use project dependencies for shared libraries across projects.
• Use file dependencies only when necessary.

By understanding these distinctions, you’ll write cleaner code, speed up build times, and set yourself up for long-term project success.

FAQ: Gradle Dependencies in Android

Q1: What’s the difference between implementation and api in Gradle?

• implementation: The dependency is only available in the current module.
• api: The dependency is exposed to modules that depend on your module.

Q2: When should I use file dependencies in Gradle?

• Only when the library isn’t available in a Maven or Gradle repository. Otherwise, prefer remote dependencies.

Q3: Can I convert a file dependency into a module or project dependency later?

• Yes. If you gain access to the source code or publish the library internally, you can switch to module/project dependencies for better maintainability.

Q4: Do Gradle dependencies affect build speed?

• Yes. Modular dependencies can improve build times, while excessive file dependencies can slow things down.