String unitName = "ObjectDbUnit";
Map persistenceUnitProps = new HashMap<String, Object>();
persistenceUnitProps.put("javax.persistence.jdbc.url", String.format("objectdb:/tmp/db/test.odb"));
JpaGraph jpaGraph = new JpaGraph(unitName, persistenceUnitProps);

String unitName = "EclipseLinkUnit";
Map persistenceUnitProps = new HashMap<String, Object>();
persistenceUnitProps.put("javax.persistence.jdbc.url", String.format("jdbc:derby:/tmp/db/;create=true"));
JpaGraph jpaGraph = new JpaGraph(unitName, persistenceUnitProps);

String unitName = "HibernateUnit";
Map persistenceUnitProps = new HashMap<String, Object>();
persistenceUnitProps.put("javax.persistence.jdbc.url", String.format("jdbc:derby:/tmp/db/;create=true"));
JpaGraph jpaGraph = new JpaGraph(unitName, persistenceUnitProps);