I'm not sure I agree that Void is a bottom type. If so, void-functions would never be able to return/terminate. Java's void is probably more of a unit type.
They allude to this later, acknowledging that it's sort of a cross between unit and bottom.
No it's not, it is 100% a unit type (except it's not really a type, since you can only use it as return type and nowhere else)
It's nice that Java has gotten those features but the article is pretty confused about type theory.