title: Support JPA and MongoDB in the same application
body: <p>there exists a requirement which sounds quite simple: support a couple of RDBMS (which i intend to do by using JPA) and MongoDB (spring-data-mongodb is preferred) for persistence. More precisely either the one or the other has to be configured and used, i'm not talking about a cross store.</p>
  
  <p>The procedure shall be the following: code the application, deliver the .war to the customer,  in a config file the customer puts the persistence information like the databaseurl (i.e. either mongodb:localhost/test or jdbc:oracle:thin:1521@foo).
  Additionally it would be nice to extend the implemenation for further datastores like couchdb.</p>
  
  <p>Is there a best practice or at least any of a non-too-much-overhead-solution which is not that dirty?</p>