Inherited Annotations

suggest change

By default class annotations do not apply to types extending them. This can be changed by adding the @Inherited annotation to the annotation definition

Example

Consider the following 2 Annotations:

@Inherited
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface InheritedAnnotationType {
}

and

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface UninheritedAnnotationType {
}

If three classes are annotated like this:

@UninheritedAnnotationType
class A {
}

@InheritedAnnotationType
class B extends A {
}

class C extends B {
}

running this code

System.out.println(new A().getClass().getAnnotation(InheritedAnnotationType.class));
System.out.println(new B().getClass().getAnnotation(InheritedAnnotationType.class));
System.out.println(new C().getClass().getAnnotation(InheritedAnnotationType.class));
System.out.println("_________________________________");
System.out.println(new A().getClass().getAnnotation(UninheritedAnnotationType.class));
System.out.println(new B().getClass().getAnnotation(UninheritedAnnotationType.class));
System.out.println(new C().getClass().getAnnotation(UninheritedAnnotationType.class));

will print a result similar to this (depending on the packages of the annotation):

null
@InheritedAnnotationType()
@InheritedAnnotationType()
_________________________________
@UninheritedAnnotationType()
null
null

Note that annotations can only be inherited from classes, not interfaces.

Found a mistake? Have a question or improvement idea? Let me know.

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