Error on em.getTransaction().commit(); using the JPA #Embeddable annotation - jpa

Question

I have some problems with #Embeddable in JAVA JPA.
I have an entity class named "Author":
#Entity
#Table(name = "author")
#XmlRootElement
#NamedQueries({
#NamedQuery(name = "Author.findAll", query = "SELECT a FROM Author a"),
...})
public class Author implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#Basic(optional = false)
#Column(name = "aID")
private Integer aID;
#Column(name = "aName")
private String aName;
#Column(name = "aSurname")
private String aSurname;
#Column(name = "aPhone")
private Integer aPhone;
#Embedded
#AttributeOverrides({
#AttributeOverride(name="city",column=#Column(name="Address")),
#AttributeOverride(name="street",column=#Column(table="Address")),
#AttributeOverride(name="number",column=#Column(table="Address"))
}) private Address address;
// set and get methods.
}
Also I have an Embeddable class named "Address":
#Embeddable
#Table(name = "Address")
#XmlRootElement
public class Address implements Serializable
{
private static final long serialVersionUID=1L;
#Column(name="city")
private String city;
#Column(name="street")
private String street;
#Column(name="number")
private int number;
// get and set methods.
}
In my main class I want to insert this values to the database. (I use mySQL) But I am getting an error on this line: em.getTransaction.commit();
public class CreateAuthor extends javax.swing.JFrame {
private static final String PERSISTENCE_UNIT_NAME = "Project";
private static EntityManagerFactory emf;
public void CreateAuthor() {
initComponents();
}
private void ekleButtonActionPerformed(java.awt.event.ActionEvent evt) {
emf = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
EntityManager em = emf.createEntityManager();
em.getTransaction().begin();
Author author = new Author();
author.setAID(3);
author.setAName("Sheldon");
author.setASurname("Smith");
author.setAPhone(768987);
Address adr = new Address();
adr.setCity("Paris");
adr.setStreet("cinar");
adr.setNumber(12);
author.setAddress(adr);
em.persist(author);
em.getTransaction().commit(); /// error occured
em.close();
}
}
On my database side, I have Author table (aID(pk),aName,aSurname,aPhone)
Address Table (city,street,number)
Do you have any idea why an error is occured?

Answer 1

The goal of Embeddable is to have fields of an object (Address) stored in the same table as the entity's table (Author -> author).
If you want to save them in another table, than Address should be an entity on its own, and there should be a OneToOne or ManyToOne association between Author and Address. The mapping, as is, don't make any sense.