Have you tried using JSONArray.getJSONObject(int), and JSONArray.length() to create your for-loop:

for (int i = 0; i < recs.length(); ++i) {
    JSONObject rec = recs.getJSONObject(i);
    int id = rec.getInt("id");
    String loc = rec.getString("loc");
    // ...
}

But how can I create a JSONArray and insert it to the JSONObject?

You can create JSONArray same like you have tried to create JSONObject.

Creating time:

For example:

JSONArray myArray = new JSONArray();
JSONObject j = new JSONObject();
j.put("key",value);
j.put("array",myArray);

Retrieving time:

you can fetch the value of String or JSONObject or any by their key name. For example:

JSONArray myArray = objJson.getJSONArray("array");