sourceSets

SourceSets are a core concept in build automation tools like Gradle, particularly for JVM-based projects. They represent collections of source code and resources that are compiled and processed together. Typically, a project will have at least two main sourceSets: main and test.

The main sourceSet usually contains the application's production code and resources. This includes files found in directories like src/main/java and src/main/resources. When you build your application for deployment, the main sourceSet is what gets compiled and packaged.

The test sourceSet, on the other hand, holds your unit and integration tests, along with any test-specific resources. Common locations are src/test/java and src/test/resources. The test sourceSet is compiled and run during the testing phase of the build lifecycle.

Build tools use sourceSets to organize project structure and define the scope of various build tasks. For example, the compileJava task typically operates on the source files defined in the main sourceSet, while the compileTestJava task operates on the source files in the test sourceSet. This separation allows for clear distinction between production code and testing code, promoting better project management and build efficiency. Projects can also define custom sourceSets to handle specific needs, such as different build variants or modules.