I'm using a snapshot of WildFly Alpha2.

Hibernate Metamodel Generator is only aware of JPA 2.0. If I use a persistence.xml with the new namespace for JPA 2.1, then I get the following (serious?) warning during compilation. Using orm.xml for JPA 2.1 results in a similar warning.

[WARNING] Hibernate JPA 2 Static-Metamodel Generator 1.2.0.Final
[WARNING] Error unmarshalling /META-INF/persistence.xml with exception :
javax.xml.bind.UnmarshalException
■with linked exception:
[org.xml.sax.SAXParseException; lineNumber: 12; columnNumber: 28; cvc-elt.1: Deklaration des Elements "persistence" kann nicht gefunden werden.]

This is the beginning of persistence.xml:
<?xml version="1.0"?>

<!--
<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 http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
version="2.0">
-->
<persistence 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"
version="2.1"> <!-- line 12 -->
<persistence-unit name="de.shop.PU">