Entitymanager query always return an empty list using JPA on a JEE webapp - maven

Question

Im dealing with a problem since a long time on my JEE Project with Maven;
My entityManager.createQuery().getResultList() always return an empty list.
The database connection is ok, Ive got data in my tables and it works perfectly well using only JDBC. I think I tried almost everything that I saw on the internet, Im just propably missing a point...
I also tried with and without EJB and moving the librairies on the WEB-INF directory if Tomcat didnt recognize them.
I tried with JPQL request as below but also with the NamedQuery annotation and still the same result.
This is my code (DAO) :
public List<Conge> getLeaves(String username) {
EntityManagerFactory entityManagerFactory = null;
EntityManager entityManager = null;
List<Conge> listLeaves = new ArrayList<Conge>();
try {
entityManagerFactory = Persistence.createEntityManagerFactory("ProjetJEE");
entityManager = entityManagerFactory.createEntityManager();
List<Employe> a = entityManager.createQuery("select c.login from Employe c").getResultList();
System.out.println("a" + a); //always empty
} finally {
if ( entityManager != null ) entityManager.close();
if ( entityManagerFactory != null ) entityManagerFactory.close();
}
return listLeaves;
}
My Employe.java (Entity) :
package org.gdc.models;
import java.io.Serializable;
import javax.persistence.*;
import java.util.List;
/**
* The persistent class for the Employe database table.
*
*/
#Entity
#NamedQuery(name="Employe.findAll", query="SELECT e FROM Employe e")
public class Employe implements Serializable {
private static final long serialVersionUID = 1L;
#Id
private String login;
private String adresse;
#Column(name="code_postal")
private String codePostal;
private String mail;
private String nom;
private String pnom;
#Column(name="solde_congés")
private int soldeCongés;
private String ville;
//bi-directional one-to-one association to Authentification
#OneToOne(mappedBy="employe")
private Authentification authentification;
//bi-directional many-to-one association to Conge
#OneToMany(mappedBy="employe")
private List<Conge> conges;
//bi-directional many-to-one association to Ref_Equipe
#ManyToOne
#JoinColumn(name="equipe")
private Ref_Equipe refEquipe;
//bi-directional many-to-one association to Ref_Fonction
#ManyToOne
#JoinColumn(name="fonction")
private Ref_Fonction refFonction;
//bi-directional many-to-one association to Rendez_vous
#OneToMany(mappedBy="employe")
private List<Rendez_vous> rendezVouses;
public Employe() {
}
public String getLogin() {
return this.login;
}
public void setLogin(String login) {
this.login = login;
}
public String getAdresse() {
return this.adresse;
}
public void setAdresse(String adresse) {
this.adresse = adresse;
}
public String getCodePostal() {
return this.codePostal;
}
public void setCodePostal(String codePostal) {
this.codePostal = codePostal;
}
public String getMail() {
return this.mail;
}
public void setMail(String mail) {
this.mail = mail;
}
public String getNom() {
return this.nom;
}
public void setNom(String nom) {
this.nom = nom;
}
public String getPnom() {
return this.pnom;
}
public void setPnom(String pnom) {
this.pnom = pnom;
}
public int getSoldeCongés() {
return this.soldeCongés;
}
public void setSoldeCongés(int soldeCongés) {
this.soldeCongés = soldeCongés;
}
public String getVille() {
return this.ville;
}
public void setVille(String ville) {
this.ville = ville;
}
public Authentification getAuthentification() {
return this.authentification;
}
public void setAuthentification(Authentification authentification) {
this.authentification = authentification;
}
public List<Conge> getConges() {
return this.conges;
}
public void setConges(List<Conge> conges) {
this.conges = conges;
}
public Conge addConge(Conge conge) {
getConges().add(conge);
conge.setEmploye(this);
return conge;
}
public Conge removeConge(Conge conge) {
getConges().remove(conge);
conge.setEmploye(null);
return conge;
}
public Ref_Equipe getRefEquipe() {
return this.refEquipe;
}
public void setRefEquipe(Ref_Equipe refEquipe) {
this.refEquipe = refEquipe;
}
public Ref_Fonction getRefFonction() {
return this.refFonction;
}
public void setRefFonction(Ref_Fonction refFonction) {
this.refFonction = refFonction;
}
public List<Rendez_vous> getRendezVouses() {
return this.rendezVouses;
}
public void setRendezVouses(List<Rendez_vous> rendezVouses) {
this.rendezVouses = rendezVouses;
}
public Rendez_vous addRendezVous(Rendez_vous rendezVous) {
getRendezVouses().add(rendezVous);
rendezVous.setEmploye(this);
return rendezVous;
}
public Rendez_vous removeRendezVous(Rendez_vous rendezVous) {
getRendezVouses().remove(rendezVous);
rendezVous.setEmploye(null);
return rendezVous;
}
}
My pom.xml :
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>ProjetJEE</groupId>
<artifactId>ProjetJEE</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<name>Leave Management System</name>
<dependencies>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.18</version>
</dependency>
<dependency>
<groupId>org.eclipse.persistence</groupId>
<artifactId>eclipselink</artifactId>
<version>2.7.5</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.10</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.persistence</groupId>
<artifactId>persistence-api</artifactId>
<version>1.0.2</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>4.0.1</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.ejb</groupId>
<artifactId>ejb-api</artifactId>
<version>3.0</version>
<scope>provided</scope>
</dependency>
</dependencies>
<build>
<sourceDirectory>src</sourceDirectory>
<resources>
<resource>
<directory>src</directory>
<excludes>
<exclude>**/*.java</exclude>
</excludes>
</resource>
</resources>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
<configuration>
<release>12</release>
</configuration>
</plugin>
<plugin>
<artifactId>maven-war-plugin</artifactId>
<version>3.2.1</version>
<configuration>
<warSourceDirectory>WebContent</warSourceDirectory>
</configuration>
</plugin>
</plugins>
</build>
</project>
And my persistence.xml :
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1"
xmlns="http://xmlns.jcp.org/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="ProjetJEE"
transaction-type="RESOURCE_LOCAL">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<class>org.gdc.models.Authentification</class>
<class>org.gdc.models.Conge</class>
<class>org.gdc.models.CongePK</class>
<class>org.gdc.models.Employe</class>
<class>org.gdc.models.Ref_Equipe</class>
<class>org.gdc.models.Ref_Etat_Conge</class>
<class>org.gdc.models.Ref_Fonction</class>
<class>org.gdc.models.Ref_Motif_Conge</class>
<class>org.gdc.models.Ref_Type_Conge</class>
<class>org.gdc.models.Rendez_vous</class>
<class>org.gdc.models.Rendez_vousPK</class>
<exclude-unlisted-classes>true</exclude-unlisted-classes>
<properties>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/ProjetJEE" />
<property name="javax.persistence.jdbc.user" value="root" />
<property name="javax.persistence.jdbc.password" value="mysql" />
<property name="javax.persistence.jdbc.driver" value="com.mysql.cj.jdbc.Driver" />
<!-- <property name="eclipselink.logging.level" value="FINE" />
<property name="eclipselink.ddl-generation" value="create-tables" /> -->
</properties>
</persistence-unit>
</persistence>
On Eclipse with JEE, Maven, Mysql, Tomcat9, JPA
If you need something else to help me, let me know...
Thanks in advance

Answer 1

The only observation I have is that you are creating EntityManager from the factory and you are not injecting it. This way I think you will find problems during the application lifecycly. You have to handle by yourself the transactions (commit, rollback, etc). I see you are closing the connections in the final block, but I don't know if you have a transaction or you need to open a new one.
Please see: PersistenceUnit vs PersistenceContext
and https://www.logicbig.com/tutorials/java-ee-tutorial/jpa/entity-context.html
I don't know why is the reason you are doing that way, but in your case I would do something like this:
public abstract class GenericDAO {
protected EntityManager entityManager;
#PersistenceContext(unitName="canvasEM")
public void setEntityManager(EntityManager entityManager) {
this.entityManager = entityManager;
}
}
#Repository
public class EmployeDAOImpl extends GenericDAO implements EmployesDAO{
public List<Employe> getEmployes() {
List<Employe> list = entityManager.createQuery("select c from Employe c").getResultList();
return list;
}
}
This is Spring, but I guess there is a way how to Inject the EntityManager directly in the EJB.