Will push a follow up shortly
> Am 22.10.2026 um 15:15 schrieb Francesco Chicchiriccò <[email protected]>:
>
> Hum, this is not what I am seeing at
>
> https://github.com/apache/openjpa/pull/220/changes#diff-b2a7225b359717a255a5118c3996fa15b43ba365c6b1812e3b20ccf064268b02R32
>
> e.g.
>
> @Converter
> public class ItemListConverter implements AttributeConverter<List<Item>,
> String> {
>
> while we have
>
> @Converter
> public class PlainAttrListConverter implements
> AttributeConverter<List<PlainAttr>, String> {
>
> On 22/10/26 15:11, Maxim Solodovnik wrote:
>> I believe you still need to change your converter to have 2 generic
>> parameters AttributeConverter<PlainAttr, ?>
>>
>> On Thu, 22 Oct 2026 at 20:06, Francesco Chicchiriccò
>> <[email protected]> wrote:
>>> So I went ahead, built the branch OPENJPA-3017 locally, then tried again
>>> with Syncope but... got the same identical stacktrace.
>>>
>>> Is there any non-default setting I should apply?
>>>
>>> Thank you.
>>> Regards.
>>>
>>> On 22/10/26 11:28, Francesco Chicchiriccò wrote:
>>>> On 22/10/26 11:24, Maxim Solodovnik wrote:
>>>>> On Thu, 22 Oct 2026 at 16:22, Francesco Chicchiriccò
>>>>> <[email protected]> wrote:
>>>>>> Hi Richard,
>>>>>> I saw (and approved) your PR, thank you!
>>>>>>
>>>>>> Related to:
>>>>>>> As an interim mapping, the converted form may serve as the persistent
>>>>>>> attribute: a String column holding the JSON, the List marked
>>>>>>> @Transient, and the two directions be done in @PrePersist/@PreUpdate
>>>>>>> and @PostLoad maybe?
>>>>>> this is the approach we follow up to Syncope 4.1.x, which is based on
>>>>>> OpenJPA 4.1.1.
>>>>>>
>>>>>> Some background information.
>>>>>> A while ago we switched to Hibernate ORM because of their support for
>>>>>> JPA 3.2 (and the license change too, of course) since it was required by
>>>>>> the Spring Boot platform upgrade.
>>>>>> OpenJPA was not ready at that time but now, considering the recent
>>>>>> efforts here, we are reconsidering; only, we would rather not loose the
>>>>>> code improvements applied so far.
>>>>>>
>>>>>> Let's see how things are going after merging your PR, fingers crossed.
>>>>> You can test from branch :)
>>>> That's also true ;-)
>>>> I cannot dedicate much time today but this is definitely something
>>>> possible, maybe I'll leave it on background and report afterwards.
>>>>
>>>>> On 21/10/26 21:48, Richard Zowalla wrote:
>>>>>>> Hi Francesco,
>>>>>>>
>>>>>>> Nothing obvious is missing. I see 2 things:
>>>>>>>
>>>>>>> The first concerns the mapping itself. @Convert applied to a collection
>>>>>>> attribute converts the elements, so List<PlainAttr> would require
>>>>>>> AttributeConverter<PlainAttr, ?> together with @ElementCollection.
>>>>>>> PlainAttrListConverter converts the collection as a whole into a single
>>>>>>> column, which Hibernate accepts but which is undefined behaviour
>>>>>>> (according to the spec), and the mapping is therefore not portable.
>>>>>>>
>>>>>>> The second concerns a defect on our side, for which we need to fill a
>>>>>>> bug. Reduced to an entity holding a List field and a whole-collection
>>>>>>> converter, OpenJPA does not register the field at all: no column is
>>>>>>> generated, and a persist followed by a find yields an empty list
>>>>>>> without an error. The sole trace is a warning that the field has no
>>>>>>> annotation indicating a persistence strategy, from which it follows
>>>>>>> that @Convert is not treated as one. Silent loss of the attribute is a
>>>>>>> more concerning outcome, more so than the exception you observed.
>>>>>>>
>>>>>>> The exception itself did not reproduce from those annotations alone,
>>>>>>> neither with a Serializable element type nor with a non-final field.
>>>>>>> Its origin is HandlerFieldStrategy.map, which installs the handler
>>>>>>> derived from the converter and then rejects columns supplied for the
>>>>>>> element; the field is thus managed in your configuration and unmanaged
>>>>>>> in my test setup. To check the difference we would need to know
>>>>>>> whether plainAttrs is declared in an orm.xml, whether any @Access,
>>>>>>> @Basic or @Column reaches it by way of Attributable, Realm or an
>>>>>>> attribute override, and which openjpa.* properties the unit sets. As an
>>>>>>> interim mapping, the converted form may serve as the persistent
>>>>>>> attribute: a String column holding the JSON, the List marked
>>>>>>> @Transient, and the two directions be done in @PrePersist/@PreUpdate
>>>>>>> and @PostLoad maybe?
>>>>>>>
>>>>>>> Gruß
>>>>>>> Richard
>>>>>>>
>>>>>>>> Am 21.10.2026 um 12:45 schrieb Francesco Chicchiriccò
>>>>>>>> <[email protected]>:
>>>>>>>>
>>>>>>>> Hi all,
>>>>>>>> I am testing OpenJPA 4.2.0-SNAPSHOT against Syncope master branch,
>>>>>>>> which is currently using Hibernate ORM 7.4.
>>>>>>>>
>>>>>>>> The first error I am encountering is related to [1] e.g.
>>>>>>>>
>>>>>>>> @Convert(converter = PlainAttrListConverter.class)
>>>>>>>> private final List<PlainAttr> plainAttrs = new ArrayList<>();
>>>>>>>>
>>>>>>>> where PlainAttr [2] is a Java bean configured for JSON serialization
>>>>>>>> and PlainAttrListConverter[3] is an AttributeConverter leveraging
>>>>>>>> Jackson for this purpose.
>>>>>>>>
>>>>>>>> This works fine under Hibernate, but throws the following exception
>>>>>>>> with OpenJPA 4.2.0-SNAPSHOT:
>>>>>>>>
>>>>>>>> <openjpa-4.2.0-SNAPSHOT-ra2c8177 fatal user error>
>>>>>>>> org.apache.openjpa.util.MetaDataException: You have supplied columns
>>>>>>>> for
>>>>>>>> "org.apache.syncope.core.persistence.jpa.entity.JPARealm.plainAttrs<element:class
>>>>>>>> org.apache.syncope.core.persistence.api.entity.PlainAttr>", but this
>>>>>>>> mapping cannot have columns in this context.
>>>>>>>> at
>>>>>>>> org.apache.openjpa.jdbc.meta.MappingInfo.assertNoSchemaComponents(MappingInfo.java:384)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.jdbc.meta.strats.HandlerFieldStrategy.map(HandlerFieldStrategy.java:84)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.jdbc.meta.FieldMapping.setStrategy(FieldMapping.java:148)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.jdbc.meta.RuntimeStrategyInstaller.installStrategy(RuntimeStrategyInstaller.java:87)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.jdbc.meta.FieldMapping.resolveMapping(FieldMapping.java:519)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.jdbc.meta.FieldMapping.resolve(FieldMapping.java:470)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.jdbc.meta.ClassMapping.resolveNonRelationMappings(ClassMapping.java:1066)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.jdbc.meta.MappingRepository.prepareMapping(MappingRepository.java:420)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.meta.MetaDataRepository.preMapping(MetaDataRepository.java:780)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.meta.MetaDataRepository.resolve(MetaDataRepository.java:667)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.meta.MetaDataRepository.getMetaDataInternal(MetaDataRepository.java:427)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.meta.MetaDataRepository.getMetaData(MetaDataRepository.java:398)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.PersistenceMetaDataDefaults.getCachedSuperclassMetaData(PersistenceMetaDataDefaults.java:355)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.PersistenceMetaDataDefaults.determineAccessType(PersistenceMetaDataDefaults.java:381)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.PersistenceMetaDataDefaults.populate(PersistenceMetaDataDefaults.java:317)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.meta.MetaDataRepository.addMetaData(MetaDataRepository.java:933)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.meta.MetaDataRepository.addMetaData(MetaDataRepository.java:918)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.AnnotationPersistenceMetaDataParser.getMetaData(AnnotationPersistenceMetaDataParser.java:828)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.AnnotationPersistenceMetaDataParser.parseClassAnnotations(AnnotationPersistenceMetaDataParser.java:582)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.AnnotationPersistenceMetaDataParser.parse(AnnotationPersistenceMetaDataParser.java:440)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.PersistenceMetaDataFactory.load(PersistenceMetaDataFactory.java:267)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.meta.MetaDataRepository.getMetaDataInternal(MetaDataRepository.java:595)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.meta.MetaDataRepository.getMetaDataInternal(MetaDataRepository.java:406)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.meta.MetaDataRepository.getMetaData(MetaDataRepository.java:398)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.PersistenceMetaDataDefaults.getCachedSuperclassMetaData(PersistenceMetaDataDefaults.java:355)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.PersistenceMetaDataDefaults.determineAccessType(PersistenceMetaDataDefaults.java:381)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.PersistenceMetaDataDefaults.populate(PersistenceMetaDataDefaults.java:317)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.meta.MetaDataRepository.addMetaData(MetaDataRepository.java:933)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.meta.MetaDataRepository.addMetaData(MetaDataRepository.java:918)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.AnnotationPersistenceMetaDataParser.getMetaData(AnnotationPersistenceMetaDataParser.java:828)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.AnnotationPersistenceMetaDataParser.parseClassAnnotations(AnnotationPersistenceMetaDataParser.java:582)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.AnnotationPersistenceMetaDataParser.parse(AnnotationPersistenceMetaDataParser.java:440)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.PersistenceMetaDataFactory.load(PersistenceMetaDataFactory.java:267)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.meta.MetaDataRepository.getMetaDataInternal(MetaDataRepository.java:595)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.meta.MetaDataRepository.getMetaDataInternal(MetaDataRepository.java:406)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.meta.MetaDataRepository.getMetaData(MetaDataRepository.java:398)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.meta.MetamodelImpl.<init>(MetamodelImpl.java:91)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.EntityManagerFactoryImpl.getMetamodel(EntityManagerFactoryImpl.java:474)
>>>>>>>> at
>>>>>>>> org.apache.openjpa.persistence.EntityManagerFactoryImpl.getMetamodel(EntityManagerFactoryImpl.java:81)
>>>>>>>>
>>>>>>>>
>>>>>>>> Is there anything obvious I am missing?
>>>>>>>>
>>>>>>>> TIA
>>>>>>>> Regards.
>>>>>>>>
>>>>>>>> [1]
>>>>>>>> https://github.com/apache/syncope/blob/master/core/persistence-jpa/src/main/java/org/apache/syncope/core/persistence/jpa/entity/JPARealm.java#L83-L84
>>>>>>>> [2]
>>>>>>>> https://github.com/apache/syncope/blob/master/core/persistence-api/src/main/java/org/apache/syncope/core/persistence/api/entity/PlainAttr.java
>>>>>>>> [3]
>>>>>>>> https://github.com/apache/syncope/blob/master/core/persistence-jpa/src/main/java/org/apache/syncope/core/persistence/jpa/converters/PlainAttrListConverter.java--
>
> --
> Francesco Chicchiriccò
>
> Tirasa - Open Source Excellence
> http://www.tirasa.net/
>
> Member at The Apache Software Foundation
> Syncope, Cocoon, Olingo, CXF, OpenJPA
> https://about.me/ilgrosso
