Meta Annotations

Meta-annotations are annotations applied to other annotations during custom declaration. They define scope boundaries, document visibility, and inheritance behavior.

Standard Meta-Annotations

• @Retention: Defines how long the annotation is kept (SOURCE, CLASS, RUNTIME).
• @Target: Restricts where the annotation can be applied (e.g. ElementType.METHOD, TYPE, FIELD).
• @Inherited: Indicates that the annotation is inherited automatically by subclasses of the annotated class.
• @Repeatable: Allows applying the same annotation multiple times on the same element (introduced in Java 8). Requires a container annotation wrapper.

Code Walkthrough

This example demonstrates how to declare a repeatable custom annotation.

import java.lang.annotation.*;
// 1. Declare Container annotation first
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
@interface Roles {
    Role[] value();
}
// 2. Declare repeatable annotation pointing to Container
@Repeatable(Roles.class)
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface Role {
    String value();
}

Interview-Relevant Information