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Groups > comp.lang.java.programmer > #37913
| From | Eric Sosman <esosman@comcast-dot-net.invalid> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: Unexpected Boxing Error at Runtime |
| Date | 2018-01-04 10:13 -0500 |
| Organization | A noiseless patient Spider |
| Message-ID | <p2lga1$7ip$1@dont-email.me> (permalink) |
| References | <p2ld0o$g4a$1@news.albasani.net> |
On 1/4/2018 9:16 AM, j4n bur53 wrote:
> Dear All,
>
> By accident I used the following code:
>
> public int getNodesCount() {
> synchronized (this) {
> return (children != null ? children.size() : null);
> }
> }
>
> It has a subtle error, namely it returns a primitive
> data type, i.e. 'int', but uses automatic boxing.
>
> But that 'null' cannot be boxed to 'int', is only
> detected at runtime, and not during compile time.
>
> Is this a bug or feature of Java?
I'd call it an "intentional bug" or "bug by design" (in the
old days we used to say "That's not a bug, that's a feature!").
JLS 5.1.7 lists the various boxing conversions, including "from
the null type to the null type," with a note that the null-null
conversion is required because the conditional operator applies
boxing conversions to its operands.
Remember, autoboxing was not present in Original Java but was
bolted on afterwards. Perhaps this is why it sometimes exhibits
certain awkwardnesses, and I think you've found a new one.
--
esosman@comcast-dot-net.invalid
Eleven hundred twelve days to go.
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Unexpected Boxing Error at Runtime j4n bur53 <janburse@fastmail.fm> - 2018-01-04 15:16 +0100
Re: Unexpected Boxing Error at Runtime Eric Douglas <e.d.programmer@gmail.com> - 2018-01-04 07:04 -0800
Re: Unexpected Boxing Error at Runtime Eric Sosman <esosman@comcast-dot-net.invalid> - 2018-01-04 10:13 -0500
Re: Unexpected Boxing Error at Runtime Eric Douglas <e.d.programmer@gmail.com> - 2018-01-04 08:01 -0800
Re: Unexpected Boxing Error at Runtime Marcel Mueller <news.5.maazl@spamgourmet.org> - 2018-01-04 18:33 +0100
Re: Unexpected Boxing Error at Runtime Kiwi User <martin@mydomain.invalid> - 2018-01-04 19:29 +0000
Re: Unexpected Boxing Error at Runtime Eric Sosman <esosman@comcast-dot-net.invalid> - 2018-01-04 15:09 -0500
Re: Unexpected Boxing Error at Runtime Daniele Futtorovic <da.futt.news@laposte.net> - 2018-01-04 21:43 +0100
Re: Unexpected Boxing Error at Runtime Arne Vajhøj <arne@vajhoej.dk> - 2018-01-04 15:53 -0500
Re: Unexpected Boxing Error at Runtime Daniele Futtorovic <da.futt.news@laposte.net> - 2018-01-05 16:06 +0100
Re: Unexpected Boxing Error at Runtime Gene Wirchenko <genew@telus.net> - 2018-01-05 09:51 -0800
Re: Unexpected Boxing Error at Runtime Daniele Futtorovic <da.futt.news@laposte.net> - 2018-01-05 20:59 +0100
Re: Unexpected Boxing Error at Runtime Eric Douglas <e.d.programmer@gmail.com> - 2018-01-05 12:15 -0800
Re: Unexpected Boxing Error at Runtime Kiwi User <martin@mydomain.invalid> - 2018-01-05 21:52 +0000
Re: Unexpected Boxing Error at Runtime Gene Wirchenko <genew@telus.net> - 2018-01-08 11:13 -0800
Re: Unexpected Boxing Error at Runtime Eric Sosman <esosman@comcast-dot-net.invalid> - 2018-01-05 16:27 -0500
Re: Unexpected Boxing Error at Runtime Daniele Futtorovic <da.futt.news@laposte.net> - 2018-01-06 00:06 +0100
Re: Unexpected Boxing Error at Runtime Kiwi User <martin@mydomain.invalid> - 2018-01-05 23:57 +0000
Re: Unexpected Boxing Error at Runtime Arne Vajhøj <arne@vajhoej.dk> - 2018-01-07 20:06 -0500
Re: Unexpected Boxing Error at Runtime bursejan@gmail.com - 2018-01-08 04:10 -0800
Re: Unexpected Boxing Error at Runtime bursejan@gmail.com - 2018-01-08 04:31 -0800
Re: Unexpected Boxing Error at Runtime Daniele Futtorovic <da.futt.news@laposte.net> - 2018-01-08 16:25 +0100
Re: Unexpected Boxing Error at Runtime Arne Vajhøj <arne@vajhoej.dk> - 2018-01-08 20:05 -0500
Re: Unexpected Boxing Error at Runtime bursejan@gmail.com - 2018-01-08 17:55 -0800
Re: Unexpected Boxing Error at Runtime Gene Wirchenko <genew@telus.net> - 2018-01-08 11:19 -0800
Re: Unexpected Boxing Error at Runtime Daniele Futtorovic <da.futt.news@laposte.net> - 2018-01-08 20:40 +0100
Re: Unexpected Boxing Error at Runtime Gene Wirchenko <genew@telus.net> - 2018-01-08 18:03 -0800
Re: Unexpected Boxing Error at Runtime Daniele Futtorovic <da.futt.news@laposte.net> - 2018-01-16 02:33 +0100
Re: Unexpected Boxing Error at Runtime bursejan@gmail.com - 2018-01-22 14:26 -0800
Re: Unexpected Boxing Error at Runtime bursejan@gmail.com - 2018-01-22 14:33 -0800
Re: Unexpected Boxing Error at Runtime Arne Vajhøj <arne@vajhoej.dk> - 2018-01-04 19:16 -0500
Re: Unexpected Boxing Error at Runtime Kiwi User <martin@mydomain.invalid> - 2018-01-05 12:17 +0000
Re: Unexpected Boxing Error at Runtime j4n bur53 <janburse@fastmail.fm> - 2018-01-05 00:13 +0100
Re: Unexpected Boxing Error at Runtime Eric Sosman <esosman@comcast-dot-net.invalid> - 2018-01-05 11:05 -0500
Re: Unexpected Boxing Error at Runtime bursejan@gmail.com - 2018-01-06 06:18 -0800
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