Part of the goals for ORM 5.0 is moving from Configuration to the ServiceRegistry+Metadata for building a SessionFactory. One of the points I ran into that will have to change is org.hibernate.persister.spi.PersisterFactory. The problems is that PersisterFactory accepts a Configuration as part of building CollectionPersisters. The need for Configuration in the standard CollectionPersister impls is amazingly trivial; we literally use it to locate the associated entity's PersistentClass to grab the classes dom4j node name, and this is right after we have just resolved the corresponding EntityPersister. The point being that the standard CollectionPersisters really don't need access to the Configuration. I am pretty sure OGM provides a custom PersisterFactory, or is it just the PersisterClassResolver that OGM provides? Also, I would assume OGM is providing custom CollectionPersister impls. This change would affect both usages. I wanted y'all to be aware of this upcoming change. But I also wanted to start a discussion about what the signature(s) should become. Currently we pass: * Configuration * Collection (the parsed mapping info) * CollectionRegionAccessStrategy * SessionFactoryImplementor I suggest we pass: * Collection * CollectionRegionAccessStrategy * SessionFactoryImplementor * Mapping (I changed order to align with the order for building EntityPersisters) Mapping is org.hibernate.engine.spi.Mapping which is part of Configuration. I decided to (at least temporarily) port this contract forward to ease migration. Metadata implements it. There is a similar discussion to be had wrt Integrators. I will follow up with an email specific to them later.