Java, Hibernate -- Can't retrieve id after persisting entity with separate embedded key class - spring

Question

I am working on a sample Springboot server application and using hibernate for JPA. I am using a generic repository pattern that performs all the CRUD operations on my entity. I am following this example :
http://www.concretepage.com/spring-boot/spring-boot-rest-jpa-hibernate-mysql-example that I came across. (My idea to have a Generic repository was to have a similar implementation for all CRUD operations, than explicitly stating one in each Service/DAO or repository implementation for each Entity) In the above example the #ID attribute is in the same class as the Entity. As a result of that I was able to persist an entity and the id would be reflected in the object after entityManager.persist(object)
In my code I have the Key class separate and it is referenced in the Entity class. On calling persist on EntityManager, a row is created in the database (since the column for the primary key is set to auto-increment in the database), but that same ID isn't reflected in the object after calling persist(). At all times my ID attribute within the key class is set to 0 that is the default int value. I would like to know if there is a way that I could fetch the ID of the inserted object either through Session or EntityManager. Also is there any alternate strategy to going about this problem without having the include the primary key in the Entity class itself. (As of now, I have looked at multiple posts on SO but haven't been able to get to a solution to my problem.)
Entity class
#Entity
#Table(name = "articles")
public class SampleArticle extends AbstractDomainObject {
/** The serialVersionUID. */
private static final long serialVersionUID = 7072648542528280535L;
/** Uniquely identifies the article. */
#EmbeddedId
#AttributeOverride(name = "articleId", column = #Column(name = "article_id"))
#GeneratedValue(strategy = GenerationType.IDENTITY)
//#GeneratedValue(strategy = GenerationType.AUTO)
private SampleArticleKey key;
/** Indicates the title. */
#Column(name = "title")
private String title;
Key class
#Embeddable
public class SampleArticleKey extends AbstractDomainKey {
/**
* Serial version id.
*/
private static final long serialVersionUID = 1325990987094850016L;
/** The article id. */
private int articleId;
Repository class
#Repository
#Transactional
public class SampleArticleRepository extends
AbstractRepository<SampleArticle, SampleArticleKey> implements
ISampleArticleRepository<SampleArticle, SampleArticleKey> {
/*
* (non-Javadoc)
* #see
* com.wpi.server.entity.repository.ISampleArticleRepository#addArticle
* (java.lang.Object)
*/
#Override
public SampleArticle create(SampleArticle article) throws Exception {
return super.create(article);
}
Abstract Repository
#Transactional
public abstract class AbstractRepository<T extends AbstractDomainObject, K
extends AbstractDomainKey> {
/** The entity manager. */
#PersistenceContext
private EntityManager entityManager;
/** The Constant LOGGER. */
private static final Logger LOGGER = Logger.getLogger(AbstractRepository.class.getName());
/**
* Persist the given object at persistence storage.
*
* #param object
* The object extending {#link AbstractDomainObject} which needs
* to be inserted.
* #return object of type {#link AbstractDomainObject} with the newly
* generated id.
* #throws Exception
* If unable to insert data.
*/
public T create(T object) throws Exception {
final Session session = entityManager.unwrap(Session.class);
session.getTransaction().begin();
session.save(object);
session.flush();
session.getTransaction().commit();
session.close();
LOGGER.fine("Entity CREATED successfully.");
return object;
};

Answer 1

Let me give you a working embeddable key example. It might help.
First overwrite equals() and hashCode() methods so that Hibernate proper identifies objects in the cash.
Now you can persist objects
Let me know if this helps or you have other issues with this.