code: private void readIdToGrant(CoronaSerializer coronaSerializer)
      throws IOException {
      coronaSerializer.readField("idToGrant");
      // Expecting the START_OBJECT token for idToGrant
      coronaSerializer.readStartObjectToken("idToGrant");
      JsonToken current = coronaSerializer.nextToken();
      while (current != JsonToken.END_OBJECT) {
        Integer id = Integer.parseInt(coronaSerializer.getFieldName());
        ResourceGrant resourceGrant =
          coronaSerializer.readValueAs(ResourceGrant.class);
        idToGrant.put(id, new ResourceGrant(resourceGrant));
        current = coronaSerializer.nextToken();
      }
      // Done with reading the END_OBJECT token for idToGrant
    }
docs: Reads the idToGrant map from a JSON stream
  
  @param coronaSerializer The CoronaSerializer instance to be used to
  read the JSON
  @throws IOException