sourceSet

A sourceSet is a fundamental concept in build systems, particularly in languages like Java and Kotlin, and is managed by build tools such as Gradle and Maven. It represents a collection of source code files and other resources that belong to a particular part of a project. These source sets are typically organized into distinct groups to facilitate different build configurations and outputs.

The most common source sets are `main` and `test`. The `main` source set includes all the production code and resources that will be compiled and packaged into the final artifact, such as a JAR file or a WAR file. This is the code that users will interact with. The `test` source set, on the other hand, contains the code and resources specifically for running automated tests. This includes unit tests, integration tests, and any supporting test data. By separating these, build systems can compile and run tests independently from the main application code.

Build tools use source sets to understand which files to include in compilation, testing, and packaging phases. Developers can define custom source sets to manage different build variants or feature modules within a project. For example, a project might have a `debug` source set for debugging-specific code and a `release` source set for optimized code. This modular approach enhances project organization and allows for flexible build configurations.