Ian McCallion wrote:
> Evan Ireland wrote:
>
>><vendor>
>>
>>With Sybase EAServer, the stubs for EJBHome and EJBObject are thread safe.
>>
>>It should be noted, however, that trying to access stateful objects from
>>multiple threads simultaneously can cause problems. For example, two
>>client threads that use UserTransaction might attempt to access the same
>>stateful session bean instance within separate transactions (at the same
>>time). This could result in an INVALID_TRANSACTION system exception for
>>one of the threads.
>>
>></vendor>
>>
>
> I find the above statement odd for two reasons:
>
> 1. Surely, whether the client threads are using user transactions or not, if you
> attempt to access the same stateful session bean from two client threads
> simultaneously then you should expect to get an error because EJBs are not
> allowed to have multiple threads running simultaneously through them and the
> server is not required (by the spec) to serialize.
>
> 2. Surely the error you should get is not specific to TRANSACTIONS? What would
> happen if using Bean-managed transactions? It is equally invalid to have two
> threads calling the SFSB but there are no transactions in sight!
You are correct. I was just giving an example. Even without a
UserTransaction, to simultaneous attempts to access a stateful
object could fail with a system exception.
> On the other hand, JBOSS also produced an INVALID_TRANSACTION exception when I
> accidentally called a SFSB on two threads, so maybe there's something I'm
> missing?
>
> ========================================
> Ian McCallion
> Alexis Systems Limited
> Romsey, UK
> Tel: +44 1794 514883
> Fax: +44 1794 501692
> ========================================
>
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>
>
>
--
_______________________________________________________________________________
Evan Ireland Sybase EAServer Engineering [EMAIL PROTECTED]
Wellington, New Zealand +64 4 934-5856
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