For such a trivial example, it's pretty easy to produce a poorly-formed JSON String of your content and let JSONObject patch it up.

In a single expression:

new JSONObject(String.format("{%s}", str.replaceAll("([^,]+),([^,]+)(,|1:$2,")))
// {"art":0,"comedy":0,"action":0,"crime":0,"animals":0}

If you really want to keep the 0.0 as Strings:

new JSONObject(String.format("{%s}", str.replaceAll("([^,]+),([^,]+)(,|1:\"$2\",")))
// {"art":"0.0","comedy":"0.0","action":"0.0","crime":"0.0","animals":"0.0"}

If you want to account for possible extraneous whitespaces:

new JSONObject(String.format("{%s}", str.replaceAll("([^,]+)\\s*?,\\s*?([^,]+)(,|1:$2,")))

.. will work with inputs like "art, 0.0, comedy, 0.0, action, 0.0, crime, 0.0, animals, 0.0" and other cases.

Disclaimer: it's not crazy-sexy code but drop in a one-line comment and it could be reasonable so long as the data structure stays simplistic.

Wrap the string in "[]" and then use the JSON parser of your choice.

If you can edit your Form class:

public class Form {

    private String listOfItems;

    public String getListOfItems() {
        return listOfItems;
    }

    public void setListOfItems(String listOfItems) {
        this.listOfItems = listOfItems;
    }

    @JsonProperty("listOfItems")
    public List<Integer> getArrayListOfItems() {
        if (listOfItems != null) {
            List<Integer> items = new ArrayList();
            for (String s : listOfItems.split(",")) {
                items.add(Integer.parseInt(s)); // May throw NumberFormatException
            }
            return items;
        }
        return null;
    }
}

By default Jackson looks for getters for serializing. You can override this by using @JsonProperty annotation.

    ObjectMapper mapper = new ObjectMapper();
    Form form = new Form();
    form.setListOfItems("1,2,3");

    System.out.print(mapper.writeValueAsString(form));

Outputs:

{"listOfItems":[1,2,3]}

You will have to create a Map:

Map<String,String> jsonMap = new HashMap<String,String>();
jsonMap.put("name","Vish");
jsonMap.put("surname","Path");
jsonMap.put("mobile","123456789");

Then use com.google.gson JSONObject: JSONObject jsonObj = new JSONObject(jsonMap);

Just remove the internal loop

String stringFromProc = "SONY,20,30,40;LG,1,4,8";
String[] array1 =  stringFromProc.split(";"); // simply use ;
// array1[0] = SONY,20,30,40
// array1[1] = LG,1,4,8

JSONObject jsonSubObject = null;
JSONObject jsonFinal = new JSONObject();
JSONArray jsonArrayRET = new JSONArray();

for(int i=0;i<array1.length;i++){
     String []array2 = array1[i].split(","); // simply use ,
     // create jsonobjects 
     // when i=0 mean for sony and next time i = 1 mean for LG  
     jsonSubObject = new JSONObject();
     jsonSubObject.put("prodName", array2[0]);
     jsonSubObject.put("mtd", array2[1]);
     jsonSubObject.put("lmtd", array2[2]);
     jsonSubObject.put("lm", array2[3]);
     // put every object in array 
     jsonArrayRET.add(jsonSubObject);
   }
     // finally put array in reported jsonobject
     jsonFinal.put("reported", jsonArrayRET);

Note : ; and , are not special regular expressions characters so no escaping \\ is required and instead of long info just read about character class []

This will convert it into an array (which is the JSON representation you specified):

var array = myString.split(',');

If you need the string version:

var string = JSON.stringify(array);

Since the string (including its double quotes) seems to be a properly formatted JSON string, we could pass it, as JSON, to the JSON processor jq and split it on the commas:

$ echo '"3.8,3.9,3.10"' | jq 'split(",")'
[
  "3.8",
  "3.9",
  "3.10"
]

Use jq with -c to get "compact output":

$ echo '"3.8,3.9,3.10"' | jq -c 'split(",")'
["3.8","3.9","3.10"]

Giving it to an internal jq variable on the command line and then splitting that variable's value:

$ jq -c -n --argjson str '"3.8,3.9,3.10"' '$str|split(",")'
["3.8","3.9","3.10"]