If you have the ability, it would be best to create a RESTful application on the server that listens for your app to contact it. Then it would take the data (send it from your app via JSON, XML or any of several other popular formats) and operate directly on the Oracle database by doing the adds/inserts/deletes there.
You can do the same thing on the way down - your app contacts the server, the server provides data from the database in the form of JSON, XML, etc and your app can then operate on it's own internal JAVA objects of data.