JPA doesn't fetch the updated data - spring

Question

I am facing a very weird issue in JPA entity manager. I have tow Entities
1) Incident
2) Country
Country is master and Incident is child with ManyToOne.
Incident.java
#Entity
#Table(name = "Incident")
public class Incident {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "incidentID")
private Integer incidentID;
#Column(name = "incidentTitle")
private String incidentTitle;
#ManyToOne
#JoinColumn(name = "countryID")
private Country country;
#Transient
#ManyToOne
#JoinColumn(name = "countryID")
public Country getCountry() {
return country;
}
public void setCountry(Country country) {
this.country = country;
}
// Getter and setters
}
Country.Java
#Entity
#Table(name="Country")
public class Country {
#Id
#Column(name="id")
#GeneratedValue(strategy=GenerationType.IDENTITY)
private Integer id;
#Column(name = "name")
private String name;
#OneToMany(mappedBy = "country", cascade = CascadeType.ALL, orphanRemoval = true)
private List<Incident> incident;
#OneToMany
#JoinColumn(
name="countryID",nullable=false)
public List<Incident> getIncident() {
return incident;
}
public void setIncident(List<Incident> incident) {
this.incident = incident;
}
//getter and setter
}
RepositoryImpl.java
#Repository
#Transactional
public class IncidentRepositoryImpl implements IncidentRepository{
#PersistenceContext
private EntityManager em;
#Autowired
public void setEntityManager(EntityManagerFactory sf) {
this.em = sf.createEntityManager();
}
#Override
public Incident addIncident(Incident incident) {
try {
em.getTransaction().begin();
em.persist(incident);
em.getTransaction().commit();
return incident;
} catch (HibernateException e) {
return null;
}
}
public Incident findById(int id) {
Incident incident = null;
incident = (Incident) em.find(Incident.class, id);
return incident;
}
}
When i add Incident, incident added successfully with countryID in Incident table, But when i try to fetch the same incident, country name comes null. But when i take restart of server or redeploy the application country name also comes. Hope there is cache issue with JAP entity manager. I try to use em.refresh(incident) in findById method, then country name comes successfully. But this refresh method is very expensive call.
Please suggest some alternate solution, how to update jpa cache automatically.

Answer 1

On your EntityManager em, add
#PersistenceContext(type = PersistenceContextType.TRANSACTION)
private EntityManager em;
With PersistenceContextType.TRANSACTION, Spring takes control of the life cycle of EntityManager