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I am trying to work out if it is possible get JPA to persist an abstract collection with concrete implementations. So far my code looks like this: @Entity public class Report extends Model { @OneToMany(mappedBy = "report",fetch=FetchType.EAGER) public Set<Item> items; } @MappedSuperclass public abstract class OpsItem extends Model { @ManyToOne public RetailOpsBranch report; } @Entity @Inheritance(strategy = InheritanceType.TABLE_PER_CLASS) public class AItem extends OpsItem { ... } @Entity @Inheritance(strategy = InheritanceType.TABLE_PER_CLASS) public class BItem extends OpsItem { ... } But I keep stumbling on the mapping error below and I don't really know if this is feasible? JPA error A JPA error occurred (Unable to build EntityManagerFactory): Use of @OneToMany or @ManyToMany targeting an unmapped class: models.Report.items[models.OpsItem] UPDATE I don't think the problem is with the abstract class but the the @MappedSuperClass annotation. It looks like jpa does not like to map the one to many relationship with a @MappedSuperClass . If I change the abstract class into a concrete class I have the same error. If I then change to @Entity annotation this seem to work with both the abstract and concrete class. This seems a bit strange to map an abstract class with @Entity . I'm I missing anything? SOLUTION Managed to figure it out with the help from rhinds. Two points to note: 1) the abstract class needs to be annotated with @Entity and inheritance strategy of table per class for the subclasses to have their own table. 2) Identity Id generation will not work in this scenario and I had to use Table generation type. @Entity @Inheritance(strategy = InheritanceType.TABLE_PER_CLASS) public abstra

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