I believe Gemstone for one. The whole idea containers could use multiple
VM's is one of the reasons that static members are illegal. The spec
mentions this once or twice.
Dave Wolf
Internet Applications Division
Sybase
> -----Original Message-----
> From: A mailing list for Enterprise JavaBeans development
> [mailto:[EMAIL PROTECTED]]On Behalf Of Luis Canals
> Sent: Tuesday, September 26, 2000 12:56 PM
> To: [EMAIL PROTECTED]
> Subject: Re: Using singleton from EJBs (not implementing singleton with
> EJ B!)
>
>
> Which EJB containers use multiple VM's?
>
> -----Original Message-----
> From: Dave Wolf [mailto:[EMAIL PROTECTED]]
> Sent: martes, 26 de septiembre de 2000 17:32
> To: [EMAIL PROTECTED]
> Subject: Re: Using singleton from EJBs (not implementing singleton with
> EJB!)
>
>
> >
> > >
> > > A singleton pattern will not be very portable. Even if the
> > static member
> > > were portable which it is not, the use of custom ClassLoaders by most
> > > containers will likely cause issues with your pattern.
> > >
> >
> > It seems it would not be portable only if you want a singleton for all
> > containers in cluster. But a singleton seems very portable and
> applicable
> > in situations where you want a singleton object per container and do not
> > need to share that singleton between multiple containers.
>
> Not necesarilly. Its of course not a singleton across containers, but it
> may not even be a singleton within the same container.
>
> 1) The container may use multiple VM's
> 2) More common, the container may use a custom ClassLoader to load the
> classes in order to support features like hot swapping. If so, the
> singleton will only be unqique across a ClassLoader. Or, a more comman
> issue would be as per the J2EE spec, each web app must have its own
> ClassLoader. Meaning the singleton is only truly a singleton within the
> single web application.
>
> Dave Wolf
> Internet Applications Division
> Sybase
>
>
>
>
> >
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