Android application development uses Gradle (http://gradle.org/) as the build system. It is used to build, test, run, and package the apps for running and testing Android applications.
Gradle is declarative and uses convention over configuration for build settings and configurations. It manages all the library dependencies for compiling and building code artifacts.
Fortunately, Android Studio abstracts most of the common Gradle tasks and operations needed for development. However, there may be some cases where having some extra knowledge about Gradle would be very helpful. We won't be digging into Gradle now, we'll be discussing it as and when needed during the course of our journey.