How does Gradle build system work internally in Android SDK?

The Gradle build system is a powerful tool that automates the process of building, testing, and packaging Android applications. It allows developers to define their build logic in a flexible way, using a Groovy-based DSL (Domain Specific Language). Here's how it works internally in the Android SDK:

1. Initialization: Gradle starts by creating a project object that represents the Android project structure, including modules, dependencies, and configurations.
2. Configuration: During the configuration phase, Gradle reads the build.gradle files and sets up the build environment. It defines tasks that need to be executed and applies plugins specific to Android.
3. Task Execution: Gradle executes tasks in a defined order. Tasks can include compiling resources, generating Java source code, compiling Java code, running tests, and packaging the APK file.
4. Build Variants: Android projects often have multiple product flavors and build types. Gradle allows developers to define different configurations for each variant, enabling flexibility in building various versions of an app.
5. Dependency Management: Gradle resolves dependencies declared in the build.gradle file, downloading them from repositories (like Maven Central or JCenter) and including them in the build process.

By utilizing these features, Gradle streamlines the development workflow and enhances the modularization of code in Android applications.