Persist for entity using JOINED inheritance, batch_size > 1 and legacy ID generation does not work in Hibernate

Issue

• An entity hierarchy is defined using JOINED inheritance:

  @Entity
  @Inheritance(strategy = InheritanceType.JOINED)
  public class Person {
      @Id
      @GeneratedValue
      private Long id;
      ...
  }
  
  @Entity
  public class Employee extends Person {
      ...
  }
  

• The persistence unit is configured to use JDBC batching and legacy ID generation:

          ...
          <property name="hibernate.jdbc.batch_size" value="20" />
          <property name="hibernate.id.new_generator_mappings" value="false" />
          ...
  

• In a batch of several entities persisted in a transaction, the final entity is not persisted fully

• The base class may be persisted but not the leaf class