db = ExternalDatabase.openDatabase( ozoneDB.toString() );
if (db == null)
throw new XMLDBException( ErrorCodes.INVALID_DATABASE, "INVALID_DATABASE" );
db.reloadClasses();
collection = CollectionImpl.forName( db, getProperty( COL_NAME ) );
if (collection == null)
throw new XMLDBException( ErrorCodes.INVALID_COLLECTION, "INVALID_COLLECTION" );