@Override
  public Object doDeserialize(Writable blob) throws SerDeException {
    try {
      List<?> row = (List<?>) jsonSerde.deserialize(blob);
      List<Object> fatRow = fatLand(row);
      return new DefaultHCatRecord(fatRow);
    } catch (Exception e) {
      throw new SerDeException(e);
    }
  }
Takes JSON string in Text form, and has to return an object representation above
it that's readable by the corresponding object inspector.

For this implementation, since we're using the jackson parser, we can construct
our own object implementation, and we use HCatRecord for it
hcatalog/core/src/main/java/org/apache/hive/hcatalog/data/JsonSerDe.java