title: Unsure if I understand TransactionAwarePersistenceManagerFactoryProxy
body: <p>I am trying to use the <code>org.springframework.orm.jdo.TransactionAwarePersistenceManagerFactoryProxy</code> in my Spring project, but I am not sure how to use it or whether it's exactly what I am looking for. I realize it can help make my DAOs work with a plain JDO <code>PersistenceManagerFactory</code>. Another question is: what happens if the proxy doesn't get made properly? Can I still use it to access my factory to create a transaction aware persistence manager? If the object managed by the factory is a singleton, does this change things? Why not just access the PersistenceManagerFactory directly? Perhaps <code>PersistenceManagerFactoryUtils.getPersistenceManager</code> would be more suited to my needs? Can <code>getObject</code> return null?</p>