net.sf.json is quite outdated

[jschmied]

This library is not updated since 2010.
Please consider moving to a maintained library:

https://www.json.org/json-en.html
https://github.com/FasterXML/jackson

[rougou]

Yes this library is very obscure and hard to customize. We ended up converting our POJO to a string first with jackson, then converting to JSONObject.
Providing POJOs to begin with like the v1 SDK would be the best option, I think...