FasterXML Jackson is a great tool for converting objects to/from POJOs.

Its a great tool when we know the structure of JSON beforehand. But what if we don’t know that? In that case we can use a Map<String, Object> to store the unknown objects. Below two links provide useful info:

http://stackoverflow.com/questions/18043587/why-im-not-able-to-unwrapp-and-serialize-java-map-using-jackson-java-library

http://www.cowtowncoder.com/blog/archives/2011/07/entry_458.html

Happy Coding :)