Annotation Interface Target

Indicates the contexts in which an annotation interface is applicable. The declaration contexts and type contexts in which an annotation interface may be applicable are specified in JLS 9.6.4.1, and denoted in source code by enum constants of java.lang.annotation.ElementType.

If an @Target meta-annotation is not present on an annotation interface T, then an annotation of type T may be written as a modifier for any declaration.

If an @Target meta-annotation is present, the compiler will enforce the usage restrictions indicated by ElementType enum constants, in line with JLS 9.7.4.

For example, this @Target meta-annotation indicates that the declared interface is itself a meta-annotation interface. It can only be used on annotation interface declarations: @Target(ElementType.ANNOTATION_TYPE) public @interface MetaAnnotationType { ... }

This @Target meta-annotation indicates that the declared class or interface is intended solely for use as a member class or interface in complex annotation interface declarations. It cannot be used to annotate anything directly: @Target({}) public @interface MemberInterface { ... }

It is a compile-time error for a single ElementType constant to appear more than once in an @Target annotation. For example, the following @Target meta-annotation is illegal: @Target({ElementType.FIELD, ElementType.METHOD, ElementType.FIELD}) public @interface Bogus { ... }