The Java Language Specification, Third Edition

9.6 Annotation Types INTERFACES
274
It is a compile-time error if an annotation type T contains an element of type
T, either directly or indirectly.
DISCUSSION
For example, this is illegal:
// Illegal self-reference!!
@interface SelfRef {
SelfRef value();
}
and so is this:
// Illegal circularity!!
@interface Ping {
Pong value();
}
@interface Pong {
Ping value();
}
Note also that this specification precludes elements whose types are nested arrays. For
example, this annotation type declaration is illegal:
// Illegal nested array!!
@interface Verboten {
String[][] value();
}
An annotation type element may have a default value specified for it. This is
done by following its (empty) parameter list with the keyword default and the
default value of the element.
Defaults are applied dynamically at the time annotations are read; default values
are not compiled into annotations. Thus, changing a default value affects
annotations even in classes that were compiled before the change was made (presuming
these annotations lack an explicit value for the defaulted element).
An ElementValue is used to specify a default value. It is a compile-time error
if the type of the element is not commensurate (§9.7) with the default value specified.
An ElementValue is always FP-strict (§15.4).
DRAFT