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 {@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 {
        ...
    }