Описание тега dagger-2
Dagger 2 is a dependency injection framework for Java and Android. It implements the full stack with generated code
Dagger 2 is a compile-time dependency injection framework for 
android and java.
It uses code generation and compile-time validation taking the approach started with Dagger 1 to it's ultimate conclusion. Dagger 2 eliminates all reflection and improves code clarity by removing the traditional ObjectGraph/Injector in favor of user-specified @Component interfaces. Dagger 2 implements the full stack with generated code.