Meta Annotations

Annotations that are used to annotate other annotations are known as meta-annotations. There are four key meta-annotations from Kotlin stdlib:

• Target: It indicates the kinds of code elements that are possible targets of an annotation. As arguments, it accepts AnnotationTarget enum values, which include values like CLASS, PROPERTY, FUNCTION, etc.

• Retention: It determines whether an annotation is stored in the binary output of compilation and is visible for reflection. By default, both are true.

• Repeatable: It determines that an annotation is applicable twice or more in a single code element.

• MustBeDocumented: It determines that an annotation is part of a public API and should therefore be included in the generated documentation for the element to which the annotation is applied.

Here are example usages of some of these annotations: