/ART-SERVER/src/conf/persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<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="art-serverPU" transaction-type="RESOURCE_LOCAL">
    <provider>org.datanucleus.store.appengine.jpa.DatastorePersistenceProvider</provider>
    <properties>
      <property name="datanucleus.ConnectionURL" value="appengine"/>
      <property name="datanucleus.NontransactionalRead" value="true"/>
      <property name="datanucleus.NontransactionalWrite" value="true"/>
    </properties>
  </persistence-unit>
</persistence>