icarus created OPENJPA-2483:
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Summary: 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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