I am relatively new to Spark and java programming. Given a json file with nested objects I need to flatten its structure(denorm the contents) and load into Elastisearch using spark.

For instance,

if the contents of my example.json is:

{
  "title": "Nest eggs",
  "body":  "Making your money work...",
  "tags":  [ "cash", "shares" ],
  "comments": 
    {
      "name":    "John Smith",
      "comment": "Great article",
      "age":     28,
      "stars":   4,
      "date":    "2014-09-01"
    }
  "owner": 
    {
      "name":    "John Smith",
      "age":     28,
    }
}

I would want to reconstruct this in the below format and load it into ES using spark.

{
  "title": "Nest eggs",
  "body":  "Making your money work...",
  "tags":  [ "cash", "shares" ],
  "comments_name": "John Smith",
  "comments_comment": "Great article",
  "comments_age":     28
  "comments_stars":   4,
  "comments_date":    "2014-09-01"
  "owner_name": "John Smith",
  "owner_age":     28,
 }

In case one of the nested objects is empty, the contents can be left empty too.

Any help is appreciated. Thanks