Error reading 'nom' on type dao.Etudiant_$$_jvst1a2_0 Hibernate - spring

Question

I want to search on a table by ID , the search work fine , but when hibernate don t find any row it s return this error :
Error reading "nom" on type dao.Etudiant , and sometimes it s return : No row with the given identifier exists:[dao.Etudiant#4]
I want to show nothing when hibernate don t find that ID on the table , need your helps thanks , I m stack my learning, I googled a lot without any solution. this is my code :
Controller :
package controller;import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import org.omg.CORBA.Request;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;
import dao.DaoEtudiant;
import dao.Etudiant;
import service.EtudiantMetier;
#Controller
public class EtudiantController {
#Autowired
EtudiantMetier service;
#RequestMapping("afficherId")
public String afficheId(Model mod,#RequestParam(value="id") Long id)
{
List <Etudiant> ets1=new ArrayList<Etudiant>();
ets1.add(service.chercheEtudiantID(id));
mod.addAttribute("etudiants",ets1);
return "etudiant1";
}
}
Class : Etudiant :
package dao;
import java.util.Date;
public class Etudiant {
private Long idEtudiant;
private String nom;
private String prenom;
private Date dateNaissance;
private String email;
public Etudiant() {
super();
}
public Long getIdEtudiant() {
return idEtudiant;
}
public void setIdEtudiant(Long idEtudiant) {
this.idEtudiant = idEtudiant;
}
public Etudiant(String nom, String prenom, Date dateNaissance, String email) {
super();
this.nom = nom;
this.prenom = prenom;
this.dateNaissance = dateNaissance;
this.email = email;
}
public String getNom() {
return nom;
}
public void setNom(String nom) {
this.nom = nom;
}
public String getPrenom() {
return prenom;
}
public void setPrenom(String prenom) {
this.prenom = prenom;
}
public Date getDateNaissance() {
return dateNaissance;
}
public void setDateNaissance(Date dateNaissance) {
this.dateNaissance = dateNaissance;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
Etudiant.hbm.xml:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated Oct 20, 2016 7:42:26 AM by Hibernate Tools 3.5.0.Final -->
<hibernate-mapping>
<class name="dao.Etudiant" table="etudiant">
<id name="idEtudiant">
<column name="ID_ETUDIANT" />
<generator class="native" />
</id>
<property name="nom" column="NOM" />
<property name="prenom" >
<column name="PRENOM" />
</property>
<property name="dateNaissance" >
<column name="DATE_NAISSANCE" />
</property>
<property name="email" >
<column name="EMAIL" />
</property>
</class>
Hibernate.cfg.xml:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="connection.driver_class"> com.mysql.jdbc.Driver</property>
<property
name="connection.url">jdbc:mysql://localhost:3306/etudes</property>
<property name="connection.username">root</property>
<property name="connection.password"></property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">100</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.current_session_context_class">thread</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<!-- Drop the existing tables and create new one -->
<property name="hibernate.hbm2ddl.auto">update</property>
<property name="hibernate.enable_lazy_load_no_trans" >
true
</property>
<!-- Mention here all the model classes along with their package name -->
<mapping resource="dao/Etudiant.hbm.xml"/>
</session-factory>
Etudiantmetierimpl.java:
#Override
public Etudiant chercheEtudiantID(Long idEtudiant) {
Session session=HibernateUtil.getSessionFactory().getCurrentSession();
session.beginTransaction();
System.out.println("avant load session");
Etudiant et=session.load (Etudiant.class, idEtudiant);
//Etudiant et=session.get (Etudiant.class, idEtudiant); // presque meme chose que load
System.out.println("apres load session et ");
session.close();
return et;
}

Answer 1

find it finally. I change this line :
Etudiant et=session.load (Etudiant.class, idEtudiant)
to :
Etudiant et=session.get (Etudiant.class, idEtudiant)
doc:
session.load()
• It will always return a “proxy” (Hibernate term) without hitting the database. In Hibernate, proxy is an object with the given identifier value, its properties are not initialized yet, it just look like a temporary fake object.
• If no row found , it will throws an ObjectNotFoundException.
session.get()
• It always hit the database and return the real object, an object that represent the database row, not proxy.
• If no row found , it return null.