JPA No Persistence provider for EntityManager

Question

I know there are some other questions on this subject, but none of the answers worked. I am new to JPA and I am using EclipseLink as implementation and Eclipse as IDE. This is my persistence.xml (it is in META-INF folder):

<?xml version="1.0" encoding="UTF-8" ?>
<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"
            version="2.0" xmlns="http://java.sun.com/xml/ns/persistence">

    <persistence-unit name="DBService" transaction-type="RESOURCE_LOCAL">
        <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>

        <class>com.maze.model.EventModel</class>
        <class>com.maze.model.StoryModel</class>

        <properties>
            <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
            <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/mazedb;create=true" />
            <property name="javax.persistence.jdbc.user" value="user" />
            <property name="javax.persistence.jdbc.password" value="pass" />

            <!-- EclipseLink should create the database schema automatically -->
            <property name="eclipselink.ddl-generation" value="create-tables" />
            <property name="eclipselink.ddl-generation.output-mode" value="database" />
        </properties>
    </persistence-unit>

</persistence>

and here I am trying to get an EntityManagerFactory

private EntityManagerFactory emf;
emf = Persistence.createEntityManagerFactory("DBService");

At runtime, I get this error: javax.persistence.PersistenceException: No Persistence provider for EntityManager named DBService

I have followed the steps from tutorials, but no results...

Edit: I have also added into WEB-INF/lib these jars: eclipselink.jar; javax.persistence_2.0.3.v201010191057.jar; mysql-connector-java-5.1.17-bin.jar, added JPA to the Project Facets but no have seen no results yet...

Answer 1

put your persistence.xml in the META-INF directory of your war file. Also, put a copy in your lib directory and the classes directory.

I am using eclipselink at work, using a standalone jar package that contains my entity classes, a MET-INF directory with the persistence.xml and it works fine.

Probably you need to make a jar file containing the entity classes, plus a MET-INF/persistence.xml, and add this jar file to your lib directory, alongside the eclipselink.jar.

The other thing to check is the RESOURCE-LOCAL, you should use this if you are using JPA in a web-app, with no entity beans components, or in a standalone application.