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Groups > comp.lang.java.programmer > #7093
| Date | 2011-08-13 14:48 -0700 |
|---|---|
| From | Patricia Shanahan <pats@acm.org> |
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: Singleton Pattern |
| References | <3be6e6cf-fa32-4503-9457-b0a1caef8f29@w11g2000vbp.googlegroups.com> |
| Message-ID | <042dnWOC1_6vbNvTnZ2dnUVZ_hydnZ2d@earthlink.com> (permalink) |
On 8/13/2011 1:56 PM, vbhavsar@gmail.com wrote:
...
> public class Singleton {
>
> private static Singleton _instance;
> private Singleton(){}
>
> private synchronized static void createInstance(){
> _instance = new Singleton();
> }
>
> public static Singleton getInstance(){
> if (_instance == null){
> createInstance();
> }
> return _instance;
> }
> }
...
> Anyone see any issues with this?
Suppose thread A calls getInstance, sees _instance to be null, calls
createInstance, and some time later thread B calls getInstance and also
sees _instance to be null. Isn't B going to go ahead and re-initialize
_instance?
If you do not think that is possible, please explain why not.
Patricia
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Singleton Pattern "vbhavsar@gmail.com" <vbhavsar@gmail.com> - 2011-08-13 13:56 -0700
Re: Singleton Pattern markspace <-@.> - 2011-08-13 14:41 -0700
Re: Singleton Pattern Patricia Shanahan <pats@acm.org> - 2011-08-13 14:48 -0700
Re: Singleton Pattern Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-08-13 16:43 -0700
Re: Singleton Pattern Ian <m4r35n357@gmail.com> - 2011-08-15 15:00 +0100
Re: Singleton Pattern Lew <lewbloch@gmail.com> - 2011-08-15 07:56 -0700
Re: Singleton Pattern Patricia Shanahan <pats@acm.org> - 2011-08-15 22:07 -0700
Re: Singleton Pattern Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-08-16 00:09 -0700
Re: Singleton Pattern Patricia Shanahan <pats@acm.org> - 2011-08-16 06:15 -0700
Re: Singleton Pattern Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-08-16 06:57 -0700
Re: Singleton Pattern Patricia Shanahan <pats@acm.org> - 2011-08-16 09:25 -0700
Re: Singleton Pattern Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-08-16 18:10 -0700
Re: Singleton Pattern Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-08-13 20:56 -0400
Re: Singleton Pattern Lew <lewbloch@gmail.com> - 2011-08-13 21:12 -0700
Re: Singleton Pattern Rajeev <rajeev.nospam@gmail.com> - 2011-08-14 06:37 -0700
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