@Documented
@TypeQualifierNickname
@Nonnegative(when=MAYBE)
@Retention(value=RUNTIME)
public @interface CheckForSigned

Used to annotate a value that may be either negative or nonnegative, and indicates that uses of it should check for negative values before using it in a way that requires the value to be nonnegative, and check for it being nonnegative before using it in a way that requires it to be negative.