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Injecting EntityManager returns null after Jboss/Wildfly migration

My application is running perfectly fine in JBoss AS 5.1.0. My goal is to migrate it to Wildfly 10.
Below is my persistence.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence" version="2.0">
<persistence-unit name="ApplicationPersistenceUnit">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<jta-data-source>java:/MySQL_DS</jta-data-source>
<jar-file>application_db_interface.jar</jar-file>
<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
<property name="jboss.entity.manager.jndi.name" value="java:/ApplicationPersistenceUnit"/>
<property name="jboss.entity.manager.factory.jndi.name" value="java:/ApplicationPersistenceUnitFactory"/>
</properties>
</persistence-unit>
</persistence>
Below is my transaction manager class;
public class TransactionManager implements TransactionManagerI {
#PersistenceContext(unitName="ApplicationPersistenceUnit")
private EntityManager em;
...
}
I also try to use lookup but it still returns null;
public Session getSession() throws DAOException {
..
em = (EntityManager) new InitialContext().lookup("java:/ApplicationPersistenceUnit");
..
}
Below is the project schema;
->application.ear
->application.ear/application.war
->application.ear/db.jar
->application.ear/db.jar/META-INF/persistence.xml
I looked into other solutions and try one by one but couldn't figure out mine yet. I can provide more info if you need.
UPDATE: I check JNDI view from wildfly admin console. I don't see ApplicationPersistenceUnit there. It looks like server doesn't bind my persistence.xml file. I am now trying to figure out this problem.

How do I use multiple databases with JPA?

I need two or more than two connections in my web application using jpa

To use different data sources, add multiple persistence units (say, source-1 and source-2 in persistence.xml and create multiple EntityManagerFactoryes by name):
EntityManagerFactory emf1 = Persistence.createEntityManagerFactory("source-1");
EntityManagerFactory emf2 = Persistence.createEntityManagerFactory("source-2");
or, if you're working on Spring or Java EE application server, inject them by name also:
#PersistenceUnit(name = "source-1")
EntityManagerFactory emf1;
#PersistenceContext(unitName = "source-2") // as an option
EntityManager em2;
persistence.xml will thus look like the following:
<?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="source-1" transaction-type="RESOURCE_LOCAL">
<properties>
<!-- source-1 properties here -->
</properties>
</persistence-unit>
<persistence-unit name="source-2" transaction-type="RESOURCE_LOCAL">
<properties>
<!-- source-2 properties here -->
</properties>
</persistence-unit>
</persistence>
Example of how to configure persistence unit, create EntityManager to manage entities and execute queries can be found here.

For single datasource jpa will use multiple connections internally.So you don't need to do anything.

Hibernate tools: persistence unit not found

I have created a Hibernate / JPA project and I'd like to create entities from tables.
While the tool works like a charm selecting a pure Hibernate configuration, in the JPA mode it does not work, claiming the absence of the persistence unit
As shown in the following photo, the persistence unit is located in the folder /src/main/resources/META-INF
This is the code of persistence.xml file:
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="socialsports" transaction-type="JTA">
<provider>org.hibernate.ejb.HibernatePersistenceProvider</provider>
<jta-data-source>jdbc/LiveDataSource</jta-data-source>
</persistence-unit>
</persistence>
This is the result of my attempt to run Hibernate tools to generate entities:

Since it only doesn't work in JPA mode, the use of the deprecated org.hibernate.ejb.HibernatePersistenceProvider could be a problem. Try org.hibernate.jpa.HibernatePersistenceProvider instead.

handle EntityManager dynamically with multiples persistences units

I have a database with multiples schemas so I have a persistence.xml file with multiples <persistence-unit /> (named 01, 02, ...).
Problematic :
I want to create an EntityManager dynamically function of some user criteria.
I have tested 2 cases.
First case : basically, I tested this code (inside stateless EJB) :
String criteria = "01";
EntityManagerFactory emf = Persistence.createEntityManagerFactory(criteria);
EntityManager em = emf.createEntityManager();
Joueur joueur = new Joueur(); // Joueur is an Entity
joueur.setPseudo("olivier");
em.persist(joueur);
but I received exception :
Caused by: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: org.postgresql.util.PSQLException: ERREUR: la transaction est annulée, les commandes sont ignorées jusqu'à la fin du bloc
de la transaction
I thought, (with help of some Stackoverflow posts), that my EntityManager wasn't "linked" to my transaction context due to the fact it wasn't injected by container.
Second case : thus, I used injection :
#PersistenceContext(unitName="00")
private EntityManager em00;
#PersistenceContext(unitName="01")
private EntityManager em01;
Code in my function :
String criteria = "01";
EntityManager em = getEm(criteria);
...
and getEm() method :
private EntityManager getEm(String criteria){
if (criteria == "00")
return em00;
else if (criteria == "01")
return em01;
return null;
}
No problem, it's work but I have to inject as many EntityManagers that I have persistence-unit.
What will be the cost if I have 50 schemas...?
Is there a way to really manage entities managers dynamically ? (1 EntityManger only)
If I have to create 1 EntityManager per schema even if I don't use it, how can I improve my code to consume the least amount of resources possible ?
Thank you for advices and feedbacks
EDIT :
My configurations files :
Persistence.xml :
<persistence version="2.0"
xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="00" transaction-type="JTA">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<jta-data-source>jdbc/sim/00</jta-data-source>
<mapping-file>orm_00_beta.xml</mapping-file>
<class>com.sim.entities.Joueur</class>
<properties>
<property name="eclipselink.ddl-generation" value="create-tables" />
</properties>
</persistence-unit>
<persistence-unit name="01" transaction-type="JTA">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<jta-data-source>jdbc/sim/01</jta-data-source>
<mapping-file>orm_01_beta2.xml</mapping-file>
<class>com.sim.entities.Joueur</class>
<properties>
<property name="eclipselink.ddl-generation" value="create-tables" />
</properties>
</persistence-unit>
</persistence>
orm_00_beta.xml :
<entity-mappings xmlns="http://java.sun.com/xml/ns/persistence/orm"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence/orm orm_2_0.xsd"
version="2.0">
<persistence-unit-metadata>
<persistence-unit-defaults>
<schema>beta</schema>
</persistence-unit-defaults>
</persistence-unit-metadata>
orm_01_beta2.xml :
<entity-mappings xmlns="http://java.sun.com/xml/ns/persistence/orm"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence/orm orm_2_0.xsd"
version="2.0">
<persistence-unit-metadata>
<persistence-unit-defaults>
<schema>beta2</schema>
</persistence-unit-defaults>
</persistence-unit-metadata>

You need to set the "eclipselink.target-server" to the application server you are using when using application managed persistence units (some servers set this automatically then using container managed persistence units). Then the EntityManager will bind with the JTA transaction that is active when it is created. If you create the EntityManager before the start of the JTA transaction then you can use joinTransaction().
If you still have issues, include the server you are using, and the full exception stack trace.
If you have a lot of schemas, you could consider using EclipseLink multi-tenant support, which allows each tenant to have their own schema.
http://www.eclipse.org/eclipselink/documentation/2.4/jpa/extensions/a_multitenant.htm#BABEGBIJ

Usually you don't have 50 schemas. I would not worry about the cost of injections, as usually EJB container has a pool of already opened connections which are ready to be injected. So the overhead is really small.
AFAIK, JPA does not allow dynamic entity managers.
If you care about resources, I would suggest to avoid using EclipseLink (I had really bad experience with EclipseLink + EJBs)
To optimize things a bit I would try to use factory pattern here. Create a Bean which will serve you EntityManagers. Instead of injecting several PersistenceContext you will have one injection with a method like:
EntityManager getEntityManager(String schemaId) {...}
Another option is to move all injections to an AbstractBean. All other beans inherit from the AbstractBean.

Two Persistence Unit in one Persistence.xml

We created some libraries that all our projects will use, this libraries will provide the basic functionality of all our systems (login, some manage, etc). But the application itself could use another database.
What we did was to create the Persistence.xml with two persist units. And package all the core library entities in a jar called "LN-model.jar" and all of the entities of out test app in "App-model.jar". But for some reason we still obtain the following message.
Could not resolve a persistence unit corresponding to the persistence-context-ref-name [x.x.x.x.listener.InicializadorListener/em] in the scope of the module called [gfdeploy#/Users/zkropotkine/WORK/SeguridadCore/dist/gfdeploy/SeguridadCore-war_war]. Please verify your application.
Here's our Persistence.xml
<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
<persistence-unit name="x" transaction-type="JTA">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<jta-data-source>jdbc/x</jta-data-source>
<jar-file>App-model.jar</jar-file>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
</properties>
</persistence-unit>
<persistence-unit name="y" transaction-type="JTA">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<jta-data-source>jdbc/y</jta-data-source>
<jar-file>LN-model.jar</jar-file>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties/>
</persistence-unit>
By the way we put the Persistence.xml in a jar, that we add to our Enterprise Project (EAR).

The problem is that the JPA does not know which is the persistence unit to use. when you have only one persistence unit this problem does not occur. To fix do the following:
You need to specify a persistence unit : #PersistenceContext(unitName="...") in the Ejb that do not have

You can add the annotations:
#PersistenceUnit(name = "x")
EntityManagerFactory entityManagerFactory;
#PersistenceContext(unitName = "y")
EntityManager entityManager;
Or you can create it manually:
EntityManagerFactory emfA = Persistence.createEntityManagerFactory("x", properties);
EntityManagerFactory emfB = Persistence.createEntityManagerFactory("y", properties);
For more details, please see the following link: https://docs.oracle.com/html/E25034_01/usingmultipledbs.htm
is very useful, to me helped me!