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https://issues.apache.org/jira/browse/OPENJPA-1804?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12912563#action_12912563
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Rick Curtis commented on OPENJPA-1804:
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Willis -
> It would have been helpful if OpenJPA had reported why it was looking for
> metadata for Object. Like "No metadata was found for type 'class
> java.lang.Object' referenced from Organization.hostNames." Also, it might be
> worth handling missing metadata for Object specially; it's more likely that
> OpenJPA has encountered a raw collection type than that the developer really
> wants Object to be persistent but has neglected to provide the metadata.
Just to be clear, this problem only happens when
openjpa.RuntimeUnenhancedClasses=supported is set?
> About the runtime enhancer, why even have it if it's half-baked?
Great question. This feature was added, turned on as the default, but never
fully completed. I think the intent was that if enough people were testing it(a
la enabled by default), we'd get all of the problems fixed and it would be nice
for out of the box usage. Unfortunately this hasn't been high enough priority
for anyone to really tackle.... In the 2.0.x release we disabled this feature
by default because of the numerous issues we've uncovered.
Perhaps we need to have a stronger warning message when this feature is
enabled? ... or disable it all together?
Thanks,
Rick
> NPE in MappingInfo.java line 1514
> ---------------------------------
>
> Key: OPENJPA-1804
> URL: https://issues.apache.org/jira/browse/OPENJPA-1804
> Project: OpenJPA
> Issue Type: Bug
> Components: Enhance
> Affects Versions: 2.0.1
> Reporter: Willis Blackburn
>
> I am encountering a NPE at MappingInfo.java line 1514. I'm sorry I don't
> have time to prepare a test case right now. I'm not even 100% sure what is
> causing the problem, but it seems to be something like this:
> I have classes Organization, Group, User, and AddressBook.
> Group has a reference (many-to-one) to Organization.
> I'm using field-level access and the Java 6 runtime enhancer. (NOT the
> build-time enhancer or the agent.)
> In ManagedClassSubclasser.prepareUnenhancedClasses, the code receives a list
> of Class objects--the ones in persistence.xml. They are not in the same
> order as they are in persistence.xml, but I don't know if that's important.
> The first one is Group. During the processing of Group, the code invokes
> ClassMapping.setTable to set the table name, which is "group_table." This
> comes from the @Table annotation of Group. So far, so good. Then the code
> does some additional processing on the relationship mappings of Group, which
> include the reference to Organization. During the processing of that
> relationship, the code calls MappingInfo.mergeJoinColumn. On line 1367, the
> method calls rel.getTable. The "rel" variable points to the ClassMapping for
> Organization. Remember that prepareUnenhancedClasses hasn't gotten to
> Organization yet--it's still working on Group--and so I assume that this
> Organization mapping was created on-demand. However, rel.getTable returns
> null. The Organization class has a @Table attribute, and I can see that the
> table name has been loaded in the ClassMappingInfo instance attached to the
> ClassMapping for Organization, however the table name has not yet been copied
> from ClassMappingInfo to ClassMapping. Later, the mergeJoinColumn method
> attempts to dereference the null table name and generates the NPE.
> Bottom line: When using the Java 6, runtime enhancer, if class A has a
> reference to class B, and both classes have @Table annotations (at least),
> and class A is processed first, then it produces a NPE.
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