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Groups > comp.lang.java.programmer > #23589
| Date | 2013-04-23 17:30 +0100 |
|---|---|
| From | lipska the kat <"nospam at neversurrender dot co dot uk"> |
| Organization | Trollbusters 3 |
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: <? extends String> |
| References | (7 earlier) <e02i4a-8m3.ln1@s.simpson148.btinternet.com> <9h4i4a-kvp.ln1@tempest.fredriksson.dy.fi> <dfgi4a-1n7.ln1@s.simpson148.btinternet.com> <IOGdnQaIDP0wN-vMnZ2dnUVZ7sSdnZ2d@bt.com> <a5ydt.5455$J9.2068@newsfe09.iad> |
| Message-ID | <j-OdnXHhU_CoKuvMnZ2dnUVZ8qednZ2d@bt.com> (permalink) |
On 23/04/13 16:50, Daniel Pitts wrote:
> On 4/23/13 8:37 AM, lipska the kat wrote:
>> On 23/04/13 14:55, Steven Simpson wrote:
>>> On 23/04/13 11:31, Donkey Hottie wrote:
>>>> 23.04.2013 12:48, Steven Simpson kirjoitti:
>>>>> public static String generateWindowsArgument(List<? extends String>
>>>>> args) {
>>>> <offtopic>java.lang.String is final, so nothing can extend it.
>>>> </offtopic>
>>>
>>> It's a matter of habit drawn from the general principle that if I don't
>>> need to modify the list, I don't impose the additional, unnecessary
>>> constraint on the caller, regardless of the element type.
>>
>> I don't understand this. In the first place List<? extends String> says
>> nothing about your ability to modify the list, you can add and remove
>> Strings to your hearts content,
> Wrong.
>
> List<? extends String> listOfStuff = new ArrayList<String>();
>
> listOfStuff.add("foo"); // compiler error here!
erk, you're right, well I never, however it doesn't say anything about
the list outside of the method, how therefor does it avoid 'impose[ing]
the additional, unnecessary constraint on the caller' what constraint
does it avoid ?
>> secondly the only type you can pass as
>> argument to generateWindowsArgument is List<String> so the construct is
>> redundant anyway In fact, given that >>extends String<< is effectively
>> meaningless I'm surprised the compiler doesn't at least issue a warning.
> In general, it is only meaningless in that String cannot be extended in
> the current implementation of String. As Steven pointed out, that may
> not be the case for future implementations, and the compiler will never
> know that.
Well I reckon there's more chance of finding Elvis serving me with my
weekly fish and chips but OK, I suppose there's a rempote possibility it
might happen one day.
>> I suppose you get away with it because compile time type erasure gets
>> rid of any type arguments and as there can be only one type of argument
>> anyway a warning would be superfluous.
> Erasure is a runtime phenomenon,
Erasure happens at compile time, generics are all about compile time
type checking, erasure removes type arguments at compile time after type
checking has occurred, the runtime system doesn't know anything about
type erasure or generics
http://docs.oracle.com/javase/tutorial/java/generics/erasure.html
[snip]
lipska
--
Lipska the Kat©: Troll hunter, sandbox destroyer
and farscape dreamer of Aeryn Sun
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exec problem is JDK 1.7.0_21 Roedy Green <see_website@mindprod.com.invalid> - 2013-04-16 15:48 -0700
Re: exec problem is JDK 1.7.0_21 Lew <lewbloch@gmail.com> - 2013-04-16 16:48 -0700
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-20 13:00 +0300
Re: exec problem is JDK 1.7.0_21 Joerg Meier <joergmmeier@arcor.de> - 2013-04-20 15:13 +0200
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-20 19:07 +0300
Re: exec problem is JDK 1.7.0_21 markspace <markspace@nospam.nospam> - 2013-04-20 09:24 -0700
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-20 19:34 +0300
Re: exec problem is JDK 1.7.0_21 markspace <markspace@nospam.nospam> - 2013-04-20 11:01 -0700
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-21 00:25 +0300
Re: exec problem is JDK 1.7.0_21 Joerg Meier <joergmmeier@arcor.de> - 2013-04-20 22:03 +0200
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-21 00:29 +0300
Re: exec problem is JDK 1.7.0_21 Martin Gregorie <martin@address-in-sig.invalid> - 2013-04-20 21:56 +0000
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-21 08:31 +0300
Re: exec problem is JDK 1.7.0_21 Martin Gregorie <martin@address-in-sig.invalid> - 2013-04-21 11:08 +0000
Re: exec problem is JDK 1.7.0_21 Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-04-21 13:43 -0300
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-21 23:12 +0300
Re: exec problem is JDK 1.7.0_21 Martin Gregorie <martin@address-in-sig.invalid> - 2013-04-21 21:17 +0000
Re: exec problem is JDK 1.7.0_21 Arne Vajhøj <arne@vajhoej.dk> - 2013-04-27 22:49 -0400
Re: exec problem is JDK 1.7.0_21 Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-04-20 15:03 -0700
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-21 08:26 +0300
Re: exec problem is JDK 1.7.0_21 "Chris Uppal" <chris.uppal@metagnostic.REMOVE-THIS.org> - 2013-04-21 14:30 +0100
Re: exec problem is JDK 1.7.0_21 Knute Johnson <nospam@knutejohnson.com> - 2013-04-21 09:20 -0700
Re: exec problem is JDK 1.7.0_21 markspace <markspace@nospam.nospam> - 2013-04-21 11:31 -0700
Re: exec problem is JDK 1.7.0_21 Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-04-21 16:06 -0300
Re: exec problem is JDK 1.7.0_21 Martin Gregorie <martin@address-in-sig.invalid> - 2013-04-21 19:47 +0000
Re: exec problem is JDK 1.7.0_21 Martin Gregorie <martin@address-in-sig.invalid> - 2013-04-21 23:01 +0000
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-21 23:29 +0300
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-21 23:45 +0300
Re: exec problem is JDK 1.7.0_21 Martin Gregorie <martin@address-in-sig.invalid> - 2013-04-21 21:38 +0000
Re: exec problem is JDK 1.7.0_21 Knute Johnson <nospam@knutejohnson.com> - 2013-04-21 18:49 -0700
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-22 09:36 +0300
Re: exec problem is JDK 1.7.0_21 Steven Simpson <ss@domain.invalid> - 2013-04-22 10:39 +0100
Re: exec problem is JDK 1.7.0_21 Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-04-22 07:43 -0700
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-22 19:33 +0300
Re: exec problem is JDK 1.7.0_21 Steven Simpson <ss@domain.invalid> - 2013-04-23 07:30 +0100
Re: exec problem is JDK 1.7.0_21 Martin Gregorie <martin@address-in-sig.invalid> - 2013-04-22 21:07 +0000
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-23 23:28 +0300
Re: exec problem is JDK 1.7.0_21 Martin Gregorie <martin@address-in-sig.invalid> - 2013-04-23 21:05 +0000
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-24 11:22 +0300
Re: exec problem is JDK 1.7.0_21 Martin Gregorie <martin@address-in-sig.invalid> - 2013-04-24 20:22 +0000
Re: exec problem is JDK 1.7.0_21 Nigel Wade <nmw@ion.le.ac.uk> - 2013-04-24 11:24 +0100
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-21 23:23 +0300
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-21 00:40 +0300
Re: exec problem is JDK 1.7.0_21 Steven Simpson <ss@domain.invalid> - 2013-04-23 10:48 +0100
Re: exec problem is JDK 1.7.0_21 Donkey Hottie <donkey@fredriksson.dy.fi> - 2013-04-23 13:31 +0300
<? extends String> (was: exec problem is JDK 1.7.0_21) Steven Simpson <ss@domain.invalid> - 2013-04-23 14:55 +0100
Re: <? extends String> lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-04-23 16:37 +0100
Re: <? extends String> Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-04-23 08:50 -0700
Re: <? extends String> lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-04-23 17:30 +0100
Re: <? extends String> Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-04-23 09:58 -0700
Re: <? extends String> Donkey Hottie <donkey@fredriksson.dy.fi> - 2013-04-23 21:06 +0300
Re: <? extends String> lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-04-23 19:33 +0100
Re: <? extends String> Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-04-23 12:26 -0700
Re: <? extends String> lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-04-24 09:08 +0100
Re: <? extends String> Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-04-23 16:28 -0300
Re: <? extends String> (was: exec problem is JDK 1.7.0_21) Lew <lewbloch@gmail.com> - 2013-04-23 14:12 -0700
Re: <? extends String> Steven Simpson <ss@domain.invalid> - 2013-04-23 23:22 +0100
Re: exec problem is JDK 1.7.0_21 Steven Simpson <ss@domain.invalid> - 2013-04-23 19:56 +0100
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-23 23:31 +0300
Re: exec problem is JDK 1.7.0_21 Steven Simpson <ss@domain.invalid> - 2013-04-23 23:39 +0100
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-24 09:29 +0300
Re: exec problem is JDK 1.7.0_21 Steven Simpson <ss@domain.invalid> - 2013-04-24 10:26 +0100
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-24 13:11 +0300
Re: exec problem is JDK 1.7.0_21 Steven Simpson <ss@domain.invalid> - 2013-04-24 22:24 +0100
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-25 11:49 +0300
Re: exec problem is JDK 1.7.0_21 Steven Simpson <ss@domain.invalid> - 2013-04-25 10:19 +0100
Re: exec problem is JDK 1.7.0_21 "Chris Uppal" <chris.uppal@metagnostic.REMOVE-THIS.org> - 2013-04-25 09:02 +0100
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-25 11:47 +0300
Re: exec problem is JDK 1.7.0_21 Steven Simpson <ss@domain.invalid> - 2013-04-25 09:50 +0100
Re: exec problem is JDK 1.7.0_21 Steven Simpson <ss@domain.invalid> - 2013-04-25 10:07 +0100
Re: exec problem is JDK 1.7.0_21 "Chris Uppal" <chris.uppal@metagnostic.REMOVE-THIS.org> - 2013-04-27 08:44 +0100
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-26 20:17 +0300
Re: exec problem is JDK 1.7.0_21 Steven Simpson <ss@domain.invalid> - 2013-04-27 09:22 +0100
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-27 12:39 +0300
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-23 23:17 +0300
Re: exec problem is JDK 1.7.0_21 Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-04-23 17:32 -0300
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-24 10:39 +0300
Re: exec problem is JDK 1.7.0_21 "Chris Uppal" <chris.uppal@metagnostic.REMOVE-THIS.org> - 2013-04-25 09:02 +0100
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-25 11:59 +0300
Re: exec problem is JDK 1.7.0_21 Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-04-25 18:38 -0300
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-28 10:57 +0300
Re: exec problem is JDK 1.7.0_21 Arne Vajhøj <arne@vajhoej.dk> - 2013-04-27 22:35 -0400
Re: exec problem is JDK 1.7.0_21 Sven Köhler <remove-sven.koehler@gmail.com> - 2013-04-28 09:23 +0300
Re: exec problem is JDK 1.7.0_21 Arne Vajhøj <arne@vajhoej.dk> - 2013-04-28 09:52 -0400
Re: exec problem is JDK 1.7.0_21 Stanimir Stamenkov <s7an10@netscape.net> - 2013-04-20 17:52 +0300
Re: exec problem is JDK 1.7.0_21 Arne Vajhøj <arne@vajhoej.dk> - 2013-04-27 22:31 -0400
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