Merge extra properties into second level JSON string

Issue

I have a Json string like:

{
 "level 1": "hello",
 "level 2" : {
    "test1": 0,
    "test2": 5,
    "test3": "this is test"
  }
}

I want to merge 2 more fields into the level 2 block (not root level). these are the following:

timeout = 5000
waityes = false

So the output JSON will be:

{
 "level 1": "hello",
 "level 2" : {
    "test1": 0,
    "test2": 5,
    "test3": "this is test",
    "timeout": 5000,
    "waityes": "false"
  }
}

I created a Kotlin data class with these 2 fields (not sure if this is the right thing to do??)

data class PropertiesToAdd(val timeout: Int = 5000, val waityes: String = "false")

But I am not sure how to merge the kotlin data class with the initial JSON string. Do I convert PropertiesToAdd to JSON first then somehow combine them??

I dont want to create model classes for the initial JSON object (the first example in this post).. (see again below)

{
 "level 1": "hello",
 "level 2" : {
    "test1": 0,
    "test2": 5,
    "test3": "this is test"
  }
}

I know I can use JSON object to merge two JSON but not sure how to add to a SECOND LEVEL element like level 2 object in the example above.

Solution

The following should work without the need for model classes:

val startJson = """
{
 "level 1": "hello",
 "level 2" : {
    "test1": 0,
    "test2": 5,
    "test3": "this is test"
  }
}"""

val endJson = JSONObject(startJson)
endJson.getJSONObject("level 2").put("timeout",5000).put("waityes","false")

endJson.toString() will be your desired output as follows:

{
 "level 1": "hello",
 "level 2" : {
    "test1": 0,
    "test2": 5,
    "test3": "this is test",
    "timeout": 5000,
    "waityes": "false"
  }
}

Answered By - Jofbr