Representing NULL in avro

[#1]

Hi All, I am trying to store CSV data to AVRO. I have issue with columns that have no value(NULL). Instead of getting nulls in the avro, it gets replaced by an empty string. What do I need to do to make sure that empty columns in CSV are represented as nulls in my avro file. My sample CSV looks like -

,12,"street 1"

and my avro schema for the same is

{
    "type": "record",
    "name": "record",
    "doc": "Schema generated by Kite",
    "fields": [
        {
            "name": "name",
            "type": [
                "null",
                "string"
            ],
            "default": null
        },
        {
            "name": "age",
            "type": [
                "null",
                "long"
            ],
            "default": null
        },
        {
            "name": "address",
            "type": [
                "null",
                "string"
            ],
            "default": null
        }
    ]
}

To verify the conversion, if I transform my AVRO to a JSON file, I get

{
  "name" : "",
  "age" : 12,
  "address" : "street 1"
}

But I expect it to be

{
  "name" : null,
  "age" : 12,
  "address" : "street 1"
}

[#2]

in the schema definition for name and address

set "default" : "null"

instead of "default": null