Article example = new Article();
example.setArticleId(60);
Identity oid = new Identity(example, ((TransactionImpl) tx).getBroker());
// 2. lookup object by OID
PersistenceBroker broker = ((TransactionImpl) tx).getBroker();
broker.clearCache();
Article b = (Article) broker.getObjectByIdentity(oid);
assertEquals("should be same object", a, b);
//System.out.println("now commit all changes...");