@Override
 @Nullable
 public EmailConfiguration load() {
   try (ODatabaseDocumentTx db = openDb()) {
     return entityAdapter.get(db);
   }
 }
 @Override
 public void save(final EmailConfiguration configuration) {
   try (ODatabaseDocumentTx db = openDb()) {
     entityAdapter.set(db, configuration);
   }
 }
 @Override
 protected void doStart() {
   try (ODatabaseDocumentTx db = databaseInstance.get().connect()) {
     entityAdapter.register(db);
   }
 }