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Posted to dev@openjpa.apache.org by "Jan Dockx (JIRA)" <ji...@apache.org> on 2008/10/31 16:09:44 UTC
[jira] Created: (OPENJPA-758) OpenJPA doesn't find ValueHandlers
with an applicable class loader
OpenJPA doesn't find ValueHandlers with an applicable class loader
------------------------------------------------------------------
Key: OPENJPA-758
URL: https://issues.apache.org/jira/browse/OPENJPA-758
Project: OpenJPA
Issue Type: Improvement
Affects Versions: 1.0.3
Environment: WebSphere 6.1, any other, 1.0.3 and probably all existing others
Reporter: Jan Dockx
Priority: Blocker
We are working with ValueHandlers for enterprise applications that
will be deployed on WebSphere, currently 6.1.0.19. We believe that the
current OpenJPA implementation has made a less than stellar choice in
how to load value handlers, and suggest a change
ValueHandlers are naturally (or so we find) specific for certain value
types, that are often dependent on the semantics of your business, and
thus are part of the application, in some way bundled in the ear you
are deploying. We do unit testing out of the container with OpenJPA
1.0.3, and everything works like a charm.
When we deploy on WebSphere however, nothing works. OpenJPA does not
find our value handlers.
Luckily OpenJPA is open source :-), so we found with certainty that
the reason is that OpenJPA tries to load the value handler with the
class loader that loaded the meta information for the property. The
class of that object is part of OpenJPA, and inside WebSphere, OpenJPA
is loaded with a class loader that has no access to the application
code, the code in the ear. So, ClassNotFoundException. Bummer.
The long term solution, we believe, is not to use the classloader
associated with the meta information for the property (i.e., the
OpenJPA class loader), but instead the class loader of the entity for
which we are working (which is also reachable via the parameters of
the method that does the loading). Using the class loader of the
actual value we want to handle is not an option, since the value can
be null. The entity however is normally also part of the application,
the ear, and cannot be null.
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[jira] Commented: (OPENJPA-758) OpenJPA doesn't find ValueHandlers
with an applicable class loader
Posted by "Kevin Sutter (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/OPENJPA-758?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12650305#action_12650305 ]
Kevin Sutter commented on OPENJPA-758:
--------------------------------------
Hi,
Just to ensure that I have discovered the same situation that you experienced, could you validate the following?
During my recent experimentation with ValueHandlers and FieldStrategies [1], I came across the situation that you describe in this JIRA. The classloading in question is in the namedHandler method on the MappingRepository class:
name = Configurations.getClassName(name);
try {
Class c = JavaTypes.classForName(name, val,
(ClassLoader) AccessController.doPrivileged(
J2DoPrivHelper.getClassLoaderAction(ValueHandler.class)));
I agree that a user-supplied class, such as a ValueHandler, should not depend on the classloader of the ValueHandler class. But, I wanted to verify that we're talking about the same area of the code.
Thanks,
Kevin
[1] http://n2.nabble.com/ValueHandlers-vs-FieldStrategies-td1573427.html
> OpenJPA doesn't find ValueHandlers with an applicable class loader
> ------------------------------------------------------------------
>
> Key: OPENJPA-758
> URL: https://issues.apache.org/jira/browse/OPENJPA-758
> Project: OpenJPA
> Issue Type: Improvement
> Affects Versions: 1.0.3
> Environment: WebSphere 6.1, any other, 1.0.3 and probably all existing others
> Reporter: Jan Dockx
> Priority: Blocker
> Original Estimate: 72h
> Remaining Estimate: 72h
>
> We are working with ValueHandlers for enterprise applications that
> will be deployed on WebSphere, currently 6.1.0.19. We believe that the
> current OpenJPA implementation has made a less than stellar choice in
> how to load value handlers, and suggest a change
> ValueHandlers are naturally (or so we find) specific for certain value
> types, that are often dependent on the semantics of your business, and
> thus are part of the application, in some way bundled in the ear you
> are deploying. We do unit testing out of the container with OpenJPA
> 1.0.3, and everything works like a charm.
> When we deploy on WebSphere however, nothing works. OpenJPA does not
> find our value handlers.
> Luckily OpenJPA is open source :-), so we found with certainty that
> the reason is that OpenJPA tries to load the value handler with the
> class loader that loaded the meta information for the property. The
> class of that object is part of OpenJPA, and inside WebSphere, OpenJPA
> is loaded with a class loader that has no access to the application
> code, the code in the ear. So, ClassNotFoundException. Bummer.
> The long term solution, we believe, is not to use the classloader
> associated with the meta information for the property (i.e., the
> OpenJPA class loader), but instead the class loader of the entity for
> which we are working (which is also reachable via the parameters of
> the method that does the loading). Using the class loader of the
> actual value we want to handle is not an option, since the value can
> be null. The entity however is normally also part of the application,
> the ear, and cannot be null.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (OPENJPA-758) OpenJPA doesn't find ValueHandlers
with an applicable class loader
Posted by "Kevin Sutter (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/OPENJPA-758?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12661606#action_12661606 ]
Kevin Sutter commented on OPENJPA-758:
--------------------------------------
Just to add another Nabble reference for this same problem.
http://n2.nabble.com/Using-custom-ValueHandler-td210193.html
Looks to be the same problem, but Catalina has proposed a change in slightly different area of the code. Maybe these are in the same callstack when this problem occurs. But, we should ensure that both cases are covered when this Issue gets resolved.
> OpenJPA doesn't find ValueHandlers with an applicable class loader
> ------------------------------------------------------------------
>
> Key: OPENJPA-758
> URL: https://issues.apache.org/jira/browse/OPENJPA-758
> Project: OpenJPA
> Issue Type: Improvement
> Affects Versions: 1.0.3
> Environment: WebSphere 6.1, any other, 1.0.3 and probably all existing others
> Reporter: Jan Dockx
> Priority: Blocker
> Original Estimate: 72h
> Remaining Estimate: 72h
>
> We are working with ValueHandlers for enterprise applications that
> will be deployed on WebSphere, currently 6.1.0.19. We believe that the
> current OpenJPA implementation has made a less than stellar choice in
> how to load value handlers, and suggest a change
> ValueHandlers are naturally (or so we find) specific for certain value
> types, that are often dependent on the semantics of your business, and
> thus are part of the application, in some way bundled in the ear you
> are deploying. We do unit testing out of the container with OpenJPA
> 1.0.3, and everything works like a charm.
> When we deploy on WebSphere however, nothing works. OpenJPA does not
> find our value handlers.
> Luckily OpenJPA is open source :-), so we found with certainty that
> the reason is that OpenJPA tries to load the value handler with the
> class loader that loaded the meta information for the property. The
> class of that object is part of OpenJPA, and inside WebSphere, OpenJPA
> is loaded with a class loader that has no access to the application
> code, the code in the ear. So, ClassNotFoundException. Bummer.
> The long term solution, we believe, is not to use the classloader
> associated with the meta information for the property (i.e., the
> OpenJPA class loader), but instead the class loader of the entity for
> which we are working (which is also reachable via the parameters of
> the method that does the loading). Using the class loader of the
> actual value we want to handle is not an option, since the value can
> be null. The entity however is normally also part of the application,
> the ear, and cannot be null.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.