May be it looks silly.. :)
But I am trying to find out what was the strong reason for IATA to choose XML over JSON.
I found lot of documentation on NDC XMLs, but couldn't find a proper functionality/feature of XML which is not possible in JSON, considering the advantages of using JSON
I could use some help in understanding it.. Thanks in advance..
A "why" question like this can be interpreted in two ways: (a) is there any historical evidence to show who made the decision, when they made it, and what their arguments were for making it? Or (b) can you think of any good reason why intelligent people might have made this choice?
I can't answer (a), but for (b) you have to look at the timeline. With something as big as IATA, it's likely they've been talking about this for at least 10 and maybe 20 years. Ten years ago, JSON was being promoted as "lightweight" - it didn't carry all the baggage of schemas, validation, transformation and query languages that went with XML. If you were in an airline, you didn't think of that as baggage, you thought of it as essential infrastructure. Being "lightweight" simply isn't a benefit in that world; on the contrary, the word is almost a suggestion that it's not up to doing heavyweight tasks.
Frankly (and at the risk of straying towards question (a)) I think it's very unlikely that the question of using JSON ever came up; they would all have been far too heavily committed to XML before anyone ever took JSON seriously. Don't forget that in 2005 XML was delivering things no one dreamt possible ten years earlier: a robust and rigorous data syntax, completely standardised, with full Unicode support, available at low cost on all platforms, with lots of tools around to support declarative processing. JSON was a new kid on the block, threatening to disrupt the consensus and fragment the industry, and for the people in this kind of community, that wasn't seen as something they needed or wanted.