What does the "ExtractAarTransform" in Gradle task "preDebugBuild" really mean?

Question

I collected the Gradle log from my daily build in Android, and I am wondering what is the meaning of

Executing transform IdentityTransform -> ExtractAarTransform -> AarTransform on artifact support-core-ui.aar (com.android.support:support-core-ui:28.0.0)

Just add the support-core-ui:28.0.0 aar to the classpath ? That's all? correct me if I'm wrong. Thanks!

Answer 1

For aar dependencies, it usually includes .jar (the class files), aidl, jni libs and resources, when you integrate it to your project, gradle tasks will extract those classes and other folders for subsequent steps to process, this is what ExtractAarTransform does, see source code ExtractAarTransform.

For AarTransform, it returns the content of an extracted AAR folder, see AarTransform