The Philosophy of Nothing

[Peter Levart]

On Wednesday 02 December 2009 17:45:19 Reinier Zwitserloot wrote:
> The 'throws' clause of any method declaration lists *CHECKED* exceptions
> that you can't throw. Thus, "throws Nothing" indicates that the method may
> throw any unchecked exception, like all methods can, and may also throw any
> instance of Nothing.
> 
> That last bit is trivially true for two reasons:
> 
> 1. There are no instances of nothing. Therefore, granting any method the
> ability to throw instances of Nothing is irrelevant.
> 
> 2. Nothing is an unchecked exception type, as it is a subtype of either
> RuntimeException or Error (it is in fact, both - Nothing is a subtype of
> everything). This is consistent with existing spec, see JLS 11.2:
> http://java.sun.com/docs/books/jls/second_edition/html/exceptions.doc.html#
> 44121
> 

and

3. Nothing is also a checked exception type, as it is as subtype of say IOException, which is a 
checked exception (unless the definition of checked exceptions in new JLS excludes Nothing from 
checked exceptions types). :-)

Peter