Dynamically add arraylist in arraylist in arraylist

Question

I am trying to add an arraylist in an arraylist in an arraylist but after the first loop in continuous to add the first array insted of the next ones..

 List<ArrayList<List<String>>> tlist= new ArrayList<>();
 List<List<String>> tslist= new ArrayList<>();
 List<String> childcat= new ArrayList<>();
 for (int i = 0; i < response.length(); i++) {
     JSONObject person = (JSONObject) response.get(i);
     for (int j = 0; j < sub.length(); j++) {
         JSONObject subobj = sub.optJSONObject(j);
         JSONArray suba = subobj.optJSONArray("SubMenus");
         childcat = new ArrayList<>();
         if(suba!=null) {
             for (int k = 0; k < suba.length(); k++) {
                 JSONObject subobja = suba.optJSONObject(k);
                 childcat.add(subtitlea);
             }
         }
         tslist.add(new ArrayList<String>(childcat));
     }
     tlist.add((new ArrayList<>(tslist)));  
 }

Answer 1

Listen @Maroun Maroun as commented on question.

If you insist on this code;

Create a new object(Arraylist) after adding it to list. It is not required create all objects before first loop. Give it a try as below

     List<ArrayList<List<String>>> tlist= new ArrayList<>();
     for (int i = 0; i < response.length(); i++) {
         JSONObject person = (JSONObject) response.get(i);
         List<List<String>> tslist= new ArrayList<>();
         for (int j = 0; j < sub.length(); j++) {
             JSONObject subobj = sub.optJSONObject(j);
             JSONArray suba = subobj.optJSONArray("SubMenus");
             List<String> childcat= new ArrayList<>();
             if(suba!=null) {
                 for (int k = 0; k < suba.length(); k++) {
                     JSONObject subobja = suba.optJSONObject(k);
                     childcat.add(subtitlea);
                 }
             }
             tslist.add(new ArrayList<String>(childcat));
         }
         tlist.add((new ArrayList<>(tslist)));  
     }