File persistence.xml of the OT/JPA example "Order-System":

<?xml version="1.0" encoding="UTF-8"?>
<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_1_0.xsd"
        version="1.0">
        <persistence-unit name="ordersystem" transaction-type="RESOURCE_LOCAL">
                <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
                <class>org.objectteams.samples.ordersystem.data.Address</class>
                <class>org.objectteams.samples.ordersystem.data.Customer</class>
                
                <class>org.objectteams.samples.ordersystem.store.StockItem</class>
                
                <class>org.objectteams.samples.ordersystem.reservation.Reservations</class>
                <class>org.objectteams.samples.ordersystem.reservation.Reservations$Reservable</class>
                <class>org.objectteams.samples.ordersystem.reservation.StockReservations</class>
                <class>org.objectteams.samples.ordersystem.reservation.StockReservations$Reservable</class>
                
                <class>org.objectteams.samples.ordersystem.order.Order</class>
                <class>org.objectteams.samples.ordersystem.order.Order$Address</class>
                <class>org.objectteams.samples.ordersystem.order.Order$Customer</class>
                <class>org.objectteams.samples.ordersystem.order.Order$Item</class>
                <class>org.objectteams.samples.ordersystem.order.StockOrder</class>
                <class>org.objectteams.samples.ordersystem.order.StockOrder$Address</class>
                <class>org.objectteams.samples.ordersystem.order.StockOrder$Customer</class>
                <class>org.objectteams.samples.ordersystem.order.StockOrder$Item</class>
                
                <properties>
                        <!-- Only report real errors. -->
                        <property name="eclipselink.logging.level" value="severe" />
                        <!--
                                Creates schema if it does not exist. Do not drop an existing schema.
                        -->
                        <property name="eclipselink.ddl-generation" value="create-tables" />
                        <property name="eclipselink.weaving" value="false" />
                        <property name="eclipselink.target-database" 
                                         value="org.eclipse.persistence.platform.database.HSQLPlatform" />
                        <property name="eclipselink.jdbc.driver" value="org.hsqldb.jdbcDriver" />
                        <property name="eclipselink.jdbc.url"
                                             value="jdbc:hsqldb:file:hsqldb/database;shutdown=true" />
                        <property name="eclipselink.jdbc.user" value="sa" />
                        <property name="eclipselink.jdbc.password" value="" />
                </properties>
        </persistence-unit>
</persistence>