android – How to post nested ArrayList<Object> in mutipart request using retrofit2-Exceptionshub

I am stuck in a weird problem for a couple of days. Actually I want to POST a nested Arraylist of object time which has file type array too in a nested array. I google this problem many times and did attempts allot but could not found a solution.
If anyone did this job earlier please share your experience with me really appreciate you.
Note: I am using retrofit2 for network calling

My object is here bellow which I have to send to the server

{
    "language_id": "1",
    "list_name": "alitown",
    "country_name":"USA",
    "list_notes": "tis ia ljasd",
    "list_cover_url": "1235689",  //optional string
    "list_cover_image": "[object] (Illuminate\Http\UploadedFile: /tmp/phpCL90BW)"  //optional image data
    "category": [{
        "cat_id":3,
        "items"[{
            "rating":2.0,
            "item_location"{
                "place_id":"Akjfkdjf578636",
                                 "name":"Location Name",
                                 "address":"This is location address",
                "lat":75.0000,
                "lng":54.8787
            }
            "item_name":"itemName",
            "item_experience":"item experience",
            "item_recomendation": "item recommendation"
            "images"[
                "image1", //multipart images or video array
                "image2" //multipart images or video array
            ]
        }]
    }]
}

Tags: androidandroid, exception, list, object, post