try-with-resources and null resource

[Bruce Chapman]

On 29/01/2011 12:05 a.m., Gernot Neppert wrote:
> 2011/1/28 Stephen Colebourne<scolebourne at joda.org>:
>> Nulls are everywhere, and using null as a return type to indicate that
>> something isn't present (like a resource) is very widespread.
>>
> I don't think anybody in this discussion would dispute your
> doubtlessly correct observation.
> Of course nulls are prevalent throughout Java code, and they serve a
> good purpose!
>
> _But_: We're not talking about property getters returning null values here.
>
> We're talking about the expressions that initialize resources, a.k.a
> expressions that modify a resource so that it ends up being in a
> 'closeable' state.
> This is a very specific subset of expressions, for which the
> presupposition that it never returns null is IMHO very reasonable.
>
>
But we are not designing a new language. We are trying to embody a 
common idiom that is difficult to get right in the current version of an 
existing language, so that it is easy to get right.

So no matter how reasonable the presupposition might be (IYHO), it is 
still wrong on account of (at least) getResourceAsStream()  (which, 
significantly, is in the java.lang package).

Bruce