If the annotation @Documented is present on the declaration of an annotation interface A, then any @A annotation on an element is considered part of the element's public contract. In more detail, when an annotation interface A is annotated with Documented, the presence and value of A annotations are a part of the public contract of the elements A annotates. Conversely, if an annotation interface B is not annotated with Documented, the presence and value of B annotations are not part of the public contract of the elements B annotates. Concretely, if an annotation interface is annotated with Documented, by default a tool like javadoc will display annotations of that interface in its output while annotations of annotation interfaces without Documented will not be displayed.