Hot debate today:
Is the text stream null valid JSON?
null
According to http://www.ietf.org/rfc/rfc4627.txt?number=4627:
...
RFC 7159 drops the limitation that a JSON text must be an object or an array. The grammar specifies:
JSON-text = ws value ws
where
value = false / null / true / object / array / number / string
Thus, "null" is now a valid JSON document.