Question on layer/peeling

Vitaly Davidovich vitalyd at gmail.com
Tue Jan 6 22:32:36 UTC 2015


Wouldn't you get an NPE here since you'd be auto unboxing a null into a
value type? I'm a bit confused about what you're trying to demonstrate.

Sent from my phone
On Jan 6, 2015 5:24 PM, "Timo Kinnunen" <timo.kinnunen at gmail.com> wrote:

> The type in bytecode will be Object, but the type in source code will be
> V, with V=boxed complex number, for example. The idiom I’m thinking of is
>
>
> Complex complex = numbers.get(nonexistentKey);
>
> if(complex == null) return;
>
> calculate(complex.re, complex.im);
>
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> (Complex is a value type, numbers is a Java 5 hash map)
>
>
> --
> Have a nice day,
> Timo.
>
> Sent from Windows Mail
>
>
>
>
>
> From: John Rose
> Sent: ‎Tuesday‎, ‎January‎ ‎6‎, ‎2015 ‎23‎:‎09
> To: Timo Kinnunen
> Cc: Brian Goetz, Michael Barker, valhalla-dev at openjdk.java.net
>
>
>
>
>
> On Jan 6, 2015, at 1:00 PM, Timo Kinnunen <timo.kinnunen at gmail.com> wrote:
> >
> > Before assigning semantics to x == null, let’s not forget boxing. What
> will happen if x is a boxed value which was returned from a call to the
> non-specialized Map.get(Object key) method?
>
> ?  Then the comparison will be false.  In any case the type of x there is
> Object, isn't it, so there's nothing new here?  — John


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