@mih_vlad,
Thank you for the article!
Though @IdClass with sequence-based identifiers works,
the second workaround for IDENTITY strategy described in your article does not work for a case
where the entity has more fields than 'registrationNumber, title, publisher_id, version'.

In that case persisting an entity throws:
java.sql.SQLException: Parameter index out of range (4 > number of parameters, which is 4).