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https://issues.apache.org/jira/browse/OPENJPA-2483?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13932997#comment-13932997
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icarus commented on OPENJPA-2483:
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Hello, thank you for your answer.
Yes I'm aware that the chances are quit low. But like I said it would already
help if it would be possible to configure each jpa implementation to behave the
same. I'm also not sure that all vendors are aware of the fact there there is
not even the possibility to configure a portable behavior.
I tried the AccessUnloaded property it woks. Thanks for pointing that out. Now
it is possible to develop portable applications for OpenJPA and Hibernate or
for EclipseLink and Hibernate.
> Detached Entities and Lazy Loading behavior breaks portability
> --------------------------------------------------------------
>
> Key: OPENJPA-2483
> URL: https://issues.apache.org/jira/browse/OPENJPA-2483
> Project: OpenJPA
> Issue Type: Bug
> Components: jpa
> Reporter: icarus
> Priority: Critical
>
> Hello everyone!
> I’ve created this bug in the EclipseLink, Hibernate and OpenJPA bugtracker
> because I think that the current situation is very unsatisfying for every
> developer that tries to develop portable Java EE applications.
> I know the JPA specification says about this:
> “When interoperability across vendors is required, the application must not
> use lazy loading”
> But is the current situation really necessary? Let me summarize the behavior
> on accessing the relations of a detached entity among the different JPA
> vendors:
> OpenJPA:
> The getter methods returns always “null” in this case. No exception is
> thrown, and no access to the database.
> I could not find a possibility to change this behavior.
> EclipseLink
> By default EclipseLink opens a new connection to the database and lazily
> fetches the relations.
> I could not find a possibility to change this behavior.
> *Hibernate*
> By default Hibernate throws LazyInitializationException.
> Since Version 4.1.6 there is a configuration parameter called
> “hibernate.enable_lazy_load_no_trans”.
> If set to true hibernate opens a read only session to the database and lazily
> fetches the relations. (Same as eclipselink does)
> This parameter is not mentioned in the official hibernate documentation. I
> found it by accident.
> So 3 Vendors 3 different behaviors and no possibility to configure a behavior
> that is support on all providers.
> I just want to say that I do not prefer a specific solution. All 3 solutions
> have their advantages and disadvantages. I do think however that this topic
> should be addressed by the JPA specification and that a there should be a
> mandatory behavior in the future.
> But for now could you (the jpa vendors) speak to another and agree on a
> common denominator? For me as developer it would enough if I could configure
> this behavior on each jpa provider with a vendor specific property. Important
> is only that there is one solution that is supported by each provider.
> Thanks for your time!
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