Hey can someone explain what is the use of ```@Retention(AnnotationRetention.BINARY)``` What is `Ret...

# android

[Vivek Modi]

Hey can someone explain what is the use of

@Retention(AnnotationRetention.BINARY)

What is Retention , AnnotationRetention and BINARY ?

[zsmb]

This is required if you want to define your own annotations (or you want to know how an existing one behaves).

The @Retention annotation controls whether usages an annotation are preserved when the code is compiled from source to binary. This matters if you want to keep the information about something being annotated available for runtime (for example, to read the annotation information using reflection).

AnnotationRetention is a simple enum that contains the available retention options. See the docs which list the available options (source, binary, runtime) and explain what they mean:
https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.annotation/-annotation-retention/

[Vivek Modi]

@zsmb what is reflection in this line Annotation is stored in binary output, but invisible for reflection

[Vivek Modi]

https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.annotation/-annotation-retention/-b-i-n-a-r-y.html

[zsmb]

This page explains reflection in the context of Kotlin: https://kotlinlang.org/docs/reflection.html

In short, it’s a way to inspect your program (e.g. classes) at runtime.

[Vivek Modi]

ok got it thanks