About Question enthuware.ocpjp.v7.2.1545 :

[renatumb]

This question is a little bit confusing.

For me:

class Barbie extends toy { // lower-case doesnt follow the rules, but there is no problem if I create a class toy and Barbie extends from it, so it would attend "Every Child has a toy, wich is of type Barbie"
}

class Child {
Barbie toy;
}

[admin]

Yes, technically, it would be valid.