Qualifier

@Target(allowedTargets = [AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.VALUE_PARAMETER])

annotation class Qualifier

Backported from jakarta inject -

Identifies qualifier annotations. Anyone can define a new qualifier. A qualifier annotation:

is annotated with {@code @Qualifier}, {@code @Retention(RUNTIME)}, and typically {@code @Documented}.
can have attributes.
may be part of the public API, much like the dependency type, but unlike implementation types which needn't be part of the public API.
may have restricted usage if annotated with {@code @Target}. While this specification covers applying qualifiers to fields and parameters only, some injector configurations might use qualifier annotations in other places (on methods or classes for example).

For example:

@java.lang.annotation.Documented
@java.lang.annotation.Retention(RUNTIME)
@jakarta.inject.Qualifier
public @interface Leather {
    Color color() default Color.TAN;
    public enum Color { RED, BLACK, TAN }
}

Qualifier

See also