LazyInitializationException Problem and need your accurate help
I've many to many relation ship with a column, So I choosed to add extra entity
I've a doctor , specialization of the doctor and a bridge entiy between the two entites contain the two primary keys plus a field named "certification"
Doctor entity:
@Entity
@Table(name = "doctors", catalog = "hospital")
@TableGenerator(name="doctors", pkColumnName="seq_name", valueColumnName="seq_count", table="sequence_table")
public class Doctor implements java.io.Serializable {
private int doctorId;
private String username;
private String password;
private double sessionPrice;
private double sessionLength;
private Set<DoctorSpecializations> doctorSpecializations = new HashSet<DoctorSpecializations>();
public Doctor() {
}
public Doctor(String username, String password,
double sessionPrice, double sessionLength) {
this.username = username;
this.password = password;
this.sessionPrice = sessionPrice;
this.sessionLength = sessionLength;
}
..........
........
}
Specilization entity:
@Entity
@Table(name = "specializations", catalog = "hospital")
@TableGenerator(name="specializations", pkColumnName="seq_name", valueColumnName="seq_count", table="sequence_table")
public class Specialization implements java.io.Serializable {
private int specId;
private String specName;
private Set<DoctorSpecializations> doctorSpecializations = new HashSet<DoctorSpecializations>();
public Specialization() {
}
public Specialization(String specName) {
this.specName = specName;
}
.......................
.......................
}
DoctorSpecializations entity:
@Entity
@Table(name="doctors_specializations", catalog="hospital")
public class DoctorSpecializations implements Serializable{
@Embeddable
private static class Id implements Serializable {
private int doctorId;
private int specId;
@Column(name="doctor_id")
public int getDoctorId() {
return doctorId;
}
public void setDoctorId(int doctorId) {
this.doctorId = doctorId;
}
@Column(name="spec_id")
public int getSpecId() {
return specId;
}
public void setSpecId(int specId) {
this.specId = specId;
}
public Id() {
}
public Id (int doctor_id, int spec_id) {
this.doctorId = doctor_id;
this.specId = spec_id;
}
public boolean equals(Object obj) {
if( obj !=null && obj instanceof Id) {
Id that = (Id) obj;
return this.getDoctorId() == that.getDoctorId() && this.getSpecId() == that.getSpecId();
}
return false;
}
public int hashCode() {
return this.getDoctorId() + this.getSpecId();
}
}
private Id id = new Id();
private String certificateDegree;
private Doctor doctor;
private Specialization spec;
public DoctorSpecializations() {
}
public DoctorSpecializations(String certificateDegree, Doctor doctor, Specialization specialization) {
this.certificateDegree = certificateDegree;
this.doctor = doctor;
this.spec = specialization;
// set identifier values
this.getId().setDoctorId(this.getDoctor().getDoctorId());
this.getId().setSpecId(this.getSpec().getSpecId());
//Guarantee referential integrity
this.doctor.getDoctorSpecializations().add(this);
this.spec.getDoctorSpecializations().add(this);
}
@EmbeddedId
public Id getId() {
return id;
}
@SuppressWarnings("unused")
private void setId(Id id) {
this.id = id;
}
@Column(name="certificate_degree")
public String getCertificateDegree() {
return certificateDegree;
}
public void setCertificateDegree(String certificateDegree) {
this.certificateDegree = certificateDegree;
}
@ManyToOne
@JoinColumn(name="doctor_id", insertable=false, updatable=false)
public Doctor getDoctor() {
return doctor;
}
public void setDoctor(Doctor doctor) {
this.doctor = doctor;
}
@ManyToOne
@JoinColumn(name="spec_id", insertable=false, updatable=false)
public Specialization getSpec() {
return spec;
}
public void setSpec(Specialization spec) {
this.spec = spec;
}
}
I've a bean method that update the doctor entiy and specialization entity and add a record in the bridge table:
public void assignSpecializationToDoctor(Specialization spec, Doctor doctor, String certificateDegree) {
em.merge(spec);
em.merge(doctor);
DoctorSpecializations docSpec = new DoctorSpecializations(certificateDegree, doctor ,spec);
em.persist(docSpec);
}
but it throws an exception:
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role:
when I try to invoke the assignSpecializationToDoctor method, I think that the problem in the Constructor of DoctorSpecializations the two lines :
this.doctor.getDoctorSpecializations().add(this); this.spec.getDoctorSpecializations().add(this);
the GetDoctorSpecializations() is called on a lazily initialized objects (doctor and spec) but in the assignSpecializationToDoctor I do update both entities before calling the collection getter method:
em.merge(spec); em.merge(doctor); DoctorSpecializations docSpec = new DoctorSpecializations(certificateDegree, doctor ,spec); em.persist(docSpec);
Please Help.
Thanks.
