Arquivo Discussoes de Programacao e Tecnologia 
Pessoal,
estou fazendo um exemplo bem básico de persistência com toplink, e na linha abaixo
public AutoresController()
{
emf = Persistence.createEntityManagerFactory("xyz");
}
surge o erro
[color=red]javax.persistence.PersistenceException: No Persistence provider for EntityManager named xyz: No META-INF/persistence.xml was found in classpath.
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:154)[/color]
Obrigado a quem puder ajudar.
cara coloca o seu persistence.xml ai pra podermos ver.
Segue o persistence.xml
<persistence 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 persistence_1_0.xsd" version="1.0">
<persistence-unit name="XYZ">
<provider>
oracle.toplink.essentials.PersistenceProvider
</provider>
<class>
meupacote.Autores
</class>
<properties>
<property name="toplink.logging.level" value="FINE" />
<property name="toplink.jdbc.driver" value="com.mysql.jdbc.Driver" />
<property name="toplink.jdbc.url" value="jdbc:mysql://localhost:3306/XYZ" />
<property name="toplink.jdbc.user" value="root" />
<property name="toplink.jdbc.password" value="root" />
</properties>
</persistence-unit>
</persistence>
então achedito que seria assim pq java e case sensitive
//seu
public AutoresController()
{
emf = Persistence.createEntityManagerFactory("xyz");
}
//novo
public AutoresController()
{
emf = Persistence.createEntityManagerFactory("XYZ");
}