Update index_.asciidoc

[mausch]

Map<String, Object> is actually poorly typed, can't represent JSON very well.

[clintongormley]

Hi @mausch

I'm not sure that this addition is helpful. It sounds more like a complaint than useful advice. Can you suggest a way of doing it better?

[mausch]

Hmm, my intention was only to amend the "very well" part. I know that people are used to represent JSON like that, and the Elasticsearch documentation is probably not the right place to teach people how to improve their usage of types.
A better way to represent JSON in Java is Gson

[kimchy]

@clintongormley lets change the docs to remove the "very well" part, and its simply just another option that we provide, similar to XContentBuilder and using Jackson for example to serialize beans.

Also, we should change the example with Jackson to not have a "String" based example, as it will perform poorly, much better to work with bytes.