@Entity
class Book(
 var name: String? = null
) {
 @Id
 @SequenceGenerator(name = "book_seq", sequenceName = "book_seq", allocationSize = 1)
 @GeneratedValue(strategy = SEQUENCE, generator = "book_seq")
 val id: Long? = null
 @OneToMany(mappedBy = "book", cascade = [PERSIST], fetch = LAZY, orphanRemoval = true)
 val descriptions: MutableSet<BookDescription> = mutableSetOf()
}
@Entity
class BookDescription(
 @EmbeddedId
 val id: BookDescriptionId,
 val description: String,
 @ManyToOne(fetch = FetchType.LAZY, cascade = [PERSIST])
 @MapsId("bookId")
 @JoinColumn(name = "book_id")
 var book: Book?
)
@Embeddable
class BookDescriptionId(
 val language: String,
) {
 var bookId: Long? = null
}

val book = Book(name = "name")
val description = BookDescription(id = BookDescriptionId(language = "EN"), description = "something", book = book)
book.descriptions.add(description)
sessionFactory.withTransaction { tx -> tx.persist(book) }