Modifying JSONObject in java , getting exception of ConcurrentModificationException

Question

I have to modify each value for key inside JSONObject and I'm using recursion to iterate over JSONObject because it can be nested. But I'm getting exception in it.next() I tried to change approach with foreach loop, fori and foreach with remainingkeys but not able to resolved.

 Iterator<String> it = myList.iterator();
                while (it.hasNext()) {
                    String value = it.next();
                    jsonObject.put(value, newValue);
              }

Complete Recursion method is something like this :

 public void handleJSON(Object input, Map<String,Object> result ){
if (input instanceof JSONObject) {
  for (String key: ((JSONObject) input).keySet()) {
    if (!(((JSONObject) input).get(key) instanceof JSONArray))
      if (((JSONObject) input).get(key) instanceof JSONObject) {
        handleJSONObject(((JSONObject) input).get(key), map);
      } else {
        Object value = ((JSONObject) input).get(key);
        ((JSONObject) input).put(key, handleValue(value, map));
      }
    else
      handleJSONObject(new JSONArray(((JSONObject) input).get(key).toString()), map);
  }

}
if (input instanceof JSONArray) {
  for (int i = 0; i < ((JSONArray) input).length(); i++) {
    JSONObject jsonObject = ((JSONArray) input).getJSONObject(i);
    handleJSONObject(jsonObject, map);
  }
}
}