<?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 persistence_2_0.xsd"
  version="2.0">
  <persistence-unit name="traida" transaction-type="RESOURCE_LOCAL">
    <class>traida.shared.domain.Contact</class>
    <properties>
      <property name="openjpa.jdbc.DBDictionary" value="hsql"/>
      <property name="javax.persistence.jdbc.url" value="jdbc:hsqldb:file:hsqldbtest;user=sa" />
      <property name="javax.persistence.jdbc.driver" value="org.hsqldb.jdbcDriver" />
      <property name="openjpa.Log" value="DefaultLevel=ERROR, Tool=ERROR" />
      <property name="openjpa.jdbc.SynchronizeMappings" value="buildSchema(ForeignKeys=true)"/>
    </properties>
  </persistence-unit>
</persistence>

Mehr zu den Properties unter http://openjpa.apache.org/builds/apache-openjpa-2.2.1-SNAPSHOT/docs/docbook/manual/main.html.

@Entity
public class Contact {
  @Id
  @GeneratedValue( strategy = GenerationType.IDENTITY )
  public Long id;
  public String name;
  // Setter/Getter ausgelassen
}

EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory( "traida" );
EntityManager entityManager = entityManagerFactory.createEntityManager();
entityManager.getTransaction().begin();
Contact c = new Contact();
c.name = "Hallo Willi";
entityManager.persist( c );
entityManager.getTransaction().commit();
System.out.println( entityManager.createQuery( "select c from Contact c" ).getResultList() );
entityManager.close();