Java Module java.base Package java.lang.annotation Annotation Type Retention（JDK11）

@Documented
@Retention(RUNTIME)
@Target(ANNOTATION_TYPE)
public @interface Retention

Indicates how long annotations with the annotated type are to be retained. If no Retention annotation is present on an annotation type declaration, the retention policy defaults to RetentionPolicy.CLASS.

A Retention meta-annotation has effect only if the meta-annotated type is used directly for annotation. It has no effect if the meta-annotated type is used as a member type in another annotation type.