@Embeddable with @CollectionTable field always non-null even if no data in joined table

[Anton_Ram]

When using @CollectionTableCollectionTable in nullable @Embedded, entity always got not-null reference even if no data. Example project to reproduce issue, contains problem entity:

When row in db contains only id and no data in joined columns expecting that data field should be null, but instead it contains not valid object

Expected :null
Actual :AddressCollection(addressString=null, fields=)

How can I change this behavior? Is it possible to use a converter, but then what types should I specify to make it work?

JDK 21
Spring Boot 3.5.6
Hibernate 6.6.29.Final

[mbladel]

Hello @Anton_Ram, I don’t think there’s a way to do this with @ElementCollection, as Hibernate has no way of distinguishing between a null association and an empty collection when there’s no record in the collection table.

Why do you need to make this distinction in the first place?

[beikov]

You could use @JdbcTypeCode(SqlTypes.JSON) val fields: List<AddressMetadata> to store the data as JSON.