AttributeConverter not working in EclipseLink, works fine in Hibernate - jpa

Question

I wanted to try a simple test case with a converter. Unfortunately it doesn't work with payara 5. It works fine with Wildfly 20.0.1. Database is H2.
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>fjp</groupId>
<artifactId>converter</artifactId>
<version>1.0</version>
<packaging>war</packaging>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
<failOnMissingWebXml>false</failOnMissingWebXml>
</properties>
<dependencies>
<dependency>
<groupId>jakarta.platform</groupId>
<artifactId>jakarta.jakartaee-api</artifactId>
<version>8.0.0</version>
<scope>provided</scope>
</dependency>
</dependencies>
</project>
persistence.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.2"
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_2.xsd"
>
<persistence-unit name="primary" transaction-type="JTA">
<!--jta-data-source>java:/TestDS</jta-data-source-->
<jta-data-source>jdbc/TestDS</jta-data-source>
<class>fjp.converter.entity.Employee</class>
<class>fjp.converter.entity.converter.StatusConverter</class>
<exclude-unlisted-classes>true</exclude-unlisted-classes>
<properties>
<property name="javax.persistence.schema-generation.database.action" value="drop-and-create" />
<property name="eclipselink.logging.level.sql" value="FINE"/>
<property name="eclipselink.logging.parameters" value="true"/>
<property name="hibernate.show_sql" value="true"/>
</properties>
</persistence-unit>
</persistence>
DAO :
package fjp.converter.dao;
import java.util.List;
import fjp.converter.entity.Employee;
public interface EmployeeDAO {
public Employee find(long i);
public void create(Employee e);
public void delete(Employee e);
public void delete(long i);
public List<Employee> findByStatus(Employee.Status status);
}
DAOImpl
package fjp.converter.dao;
import java.util.List;
import javax.ejb.Stateless;
import javax.persistence.PersistenceContext;
import javax.persistence.EntityManager;
import fjp.converter.entity.Employee;
#Stateless
public class EmployeeDAOImpl implements EmployeeDAO {
#PersistenceContext
private EntityManager em;
public Employee find(long i) {
return em.find(Employee.class, i);
}
#Override
public void create(Employee e) {
em.persist(e);
}
#Override
public void delete(long i) {
var e = this.find(i);
if(e != null) em.remove(e);
}
#Override
public void delete(Employee e) {
if(e == null) return;
delete(e.getId());
}
#Override
public List<Employee> findByStatus(Employee.Status status) {
return em.createNamedQuery("Employee.findByStatus", Employee.class)
.setParameter("status", status)
.getResultList();
}
}
Entity :
package fjp.converter.entity;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.AttributeConverter;
import javax.persistence.Convert;
import javax.persistence.NamedQuery;
import java.io.Serializable;
#NamedQuery(name="Employee.findByStatus", query="select e from Employee e where e.status=:status")
#Entity
public class Employee implements Serializable{
public enum Status {
SENIOR("SENIOR"),
JUNIOR("JUNIOR");
private String code;
private Status(String s) {
this.code = s;
}
public String getCode() {
return this.code;
}
}
#Id
private long id;
#Convert(converter = fjp.converter.entity.converter.StatusConverter.class)
private Status status;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public Status getStatus() {
return this.status;
}
public void setStatus(Status s) {
this.status = s;
}
#Override
public String toString() {
return String.format("id=%d, status=%s", id, status == null ? null : status.getCode());
}
}
Converter :
package fjp.converter.entity.converter;
import javax.persistence.Converter;
import javax.persistence.AttributeConverter;
import fjp.converter.entity.Employee.Status;
#Converter
public class StatusConverter implements AttributeConverter<Status, String> {
#Override
public String convertToDatabaseColumn(Status e) {
return e == null ? null : e.getCode();
}
#Override
public Status convertToEntityAttribute(String s) {
if(s == null) return null;
switch(s) {
case "SENIOR": return Status.SENIOR;
case "JUNIOR": return Status.JUNIOR;
default: return null;
}
}
}
Servlet
package fjp.converter.servlet;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServlet;
import fjp.converter.dao.EmployeeDAO;
import fjp.converter.entity.Employee;
import fjp.converter.entity.Employee.Status;
import javax.inject.Inject;
#WebServlet("/test")
public class Test extends HttpServlet {
#Inject
private EmployeeDAO dao;
#Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) {
Employee e = new Employee();
long id = 1;
dao.delete(id);
e.setId(id);
e.setStatus(Status.SENIOR);
dao.create(e);
id = 2;
dao.delete(id);
e.setId(id);
e.setStatus(Status.JUNIOR);
dao.create(e);
Status status = Status.SENIOR;
var list = dao.findByStatus(status);
for(var o : list) {
System.out.println(o);
if(o.getStatus() != status) {
System.out.println("ERROR !!!!!");
}
}
status = Status.JUNIOR;
list = dao.findByStatus(status);
for(var o : list) {
System.out.println(o);
if(o.getStatus() != status) {
System.out.println("ERROR !!!!!");
}
}
}
}
First time you ask the servlet you get the error message :
[2021-05-13T19:08:07.512+0200] [Payara 5.2021.3] [PRÉCIS] [] [org.eclipse.persistence.session./file:/home/frederic/payara5/glassfish/domains/domain1/applications/converter-1.0/WEB-INF/classes/_primary.sql] [tid: _ThreadID=76 _ThreadName=http-thread-pool::http-listener-1(5)] [timeMillis: 1620925687512] [levelValue: 500] [[
SELECT ID, STATUS FROM EMPLOYEE WHERE (STATUS = ?)
bind => [SENIOR]]]
[2021-05-13T19:08:07.514+0200] [Payara 5.2021.3] [INFOS] [] [] [tid: _ThreadID=76 _ThreadName=http-thread-pool::http-listener-1(5)] [timeMillis: 1620925687514] [levelValue: 800] [[
id=2, status=JUNIOR]]
[2021-05-13T19:08:07.514+0200] [Payara 5.2021.3] [INFOS] [] [] [tid: _ThreadID=76 _ThreadName=http-thread-pool::http-listener-1(5)] [timeMillis: 1620925687514] [levelValue: 800] [[
ERROR !!!!!]]
If you refresh the page : it blows !
Local Exception Stack:
Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.7.7.payara-p3): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: org.h2.jdbc.JdbcSQLException: Violation dindex unique ou clé primaire: {0}
Unique index or primary key violation: {0}; SQL statement:
INSERT INTO EMPLOYEE (ID, STATUS) VALUES (?, ?) [23505-197]

Answer 1

The problem is you are editing an object after you call persist on it in ways not allowed by the JPA specification. What is happening here is you first create Employee e and set its ID and status (1, SENIOR), and call persist on this instance.
You then change the id and status values on e (2, JUNIOR) and again call persist on that same instance. Instance E though is already persisted, so this is ignored. When you query for status SENIOR, EclipseLink will query and find a row matching (1, SENIOR), but when it goes to the cache to look to see if it already has the data, it'll find your 'e' instance and so just return that. Your application logs an error because you've change the state of e to JUNIOR.
For proof of what is happening - try listing out what is in the database.
The solution is just to create a second Employee instance to represent the (2,JUNIOR) data.
Some differences in JPA providers are that EclipseLink will maintain 1st and 2nd level caches by default. This interferes with this situation because you are modifying objects in ways not allowed within the JPA spec, and EclipseLink remembers the data for longer than if there wasn't a cache. You are not allowed to modify primary keys within JPA.

Answer 2

It works if I add to persistence.xml :
<shared-cache-mode>ENABLE_SELECTIVE</shared-cache-mode>
So you can reuse the Employe but beware of second level cache.