Groovy parse Json preserve keys order - json

Question

I try to parse a Json in groovy/Jenkins(I have no access to readJSON step) and keep the json keys order.
After my research, I found that groovy Map/HashMap objects are not preserving the order of the keys.
The only type which keeping order is LinkedHashMap So I try to convert the output of JsonSlurper.parseText to linkedhashmap but it still changing the items order
def jsonstr = """
{
"Id": 533,
"StartTime": "2022-05-10 11:56:18",
"EndTime": "2022-05-10 11:58:49",
"TimeShift": "N/A",
"Run": "123",
"Setup": "Test",
"Version": "3.17",
"Result": "pass",
"DebugMode": 1,
"NumberOfCores": 3,
}
"""
//init as LinkedHashMap
LinkedHashMap map = new LinkedHashMap()
map = (LinkedHashMap) (new JsonSlurperClassic().parseText(jsonstr))
println(map)
/*
the output is in incorrect order, I expect to get `Id` attribute as a first key but I'm getting:
[EndTime:2022-05-10 11:58:49, Version:3.17, TimeShift:N/A, StartTime:2022-05-10 11:56:18, DebugMode:1, Run:123, NumberOfCores:3, Id:533, Setup:Test, Result:pass]
*/

Answer 1

Here is the solution:
I realized that readJSON step is keeping the order so I try to take a look at its implementation.
readJSON uses net.sf.json.* library, in this library there is an option to parse string to jsonObject (with keeping the order of the keys!) by:
import net.sf.json.JSONSerializer
def map = JSONSerializer.toJSON(jsonstr)
println(map)
NOTES:
if you want use it during a pipeline I suggest you to use readJSON step itself, otherwise, you'll need to approve this function from Manage Jenkins -> script approval
In this method empty properties will be net.sf.json.JSONNull
which holds a textual value "null" -> if (someEmptyKey != null) always returns true (also when null) to avoid that, use:
if (!someEmptyKey instanceof JSONNull )
Sources: docs, jenkins-implementation