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 not possible to instantiate or assign, which is more like a never type than a unit; and it is not possible to define new types with the same properties, which is also more like bottom than unit. But you're right that it's not actually a true never type since it can't represent function divergence.
  
  I think the truth is just that Java's type system isn't very mathematically disciplined.
  
  It's not possible to instantiate or assign, which is more like a never type than a unit
  
  Actually, this is because void is not a type, it is just a keyword, a placeholder used instead of the return type when a function doesn't return anything.
  
  If it were a bottom type, that would mean that a method returning void must diverge, which is simply not true.
  
  Also, if it were a bottom type, it would be possible to write an "unreachable" method
  
  void unreachable(void bottom) { return bottom; }
  
  Even though it couldn't be called, it should be possible to define it, if void was a bottom type. But it is not, because void isn't a bottom type, it's no type at all.
  
  The post has been edited; it looks like someone on reddit made essentially the same point. You're right of course that void isn't a true type in Java, but the post now also discusses Void, which I suppose just shows how void infects the type system despite not being a type.

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