INSERT JSON TO SQLite - ANDROID

I am trying to query a json from a local server and insert it into SQLite but it is not inserting it.

    public void cargarTrabajadores() {

    RequestQueue requestQueve = Volley.newRequestQueue(this);

    JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(
            Request.Method.GET,
            url,
            null,
            new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    try {
                       JSONArray trabajadores  = response.getJSONArray("o110");
                        for (int i = 0 ; i< trabajadores.length(); i++){
                            JSONObject trabajador   = trabajadores.getJSONObject(i);
                            String dni = trabajador.getString("codigo");
                            String nombre = trabajador.getString("nombre");

                            ingresarSlite(nombre,dni);
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {

                }
            }

    );
    requestQueve.add(jsonObjectRequest);
}

public void ingresarSlite(String nom,  String dni) {

            SqliteHelper cnn = new SqliteHelper(this, "BD",  null,1);

            SQLiteDatabase db = cnn.getWritableDatabase();

            ContentValues values = new ContentValues();

            values.put("dni",dni.toString());
            values.put("nombre",nom.toString());

           db.insert("trabajador",null,values); 
}

And this is the json format:

{"o110":[
{"id":"1","codigo":"19704860","ipspat":null,"ipsmat":null,"ipsnom":null,"ipsnom1":null,"nombre":"LLAURY NINAQUISPE, ALONSO ANDRES"},
{"id":"2","codigo":"19673992","ipspat":null,"ipsmat":null,"ipsnom":null,"ipsnom1":null,"nombre":"POLO AGREDA, SANTOS FELIPE"}],"o120":[{"id":"207","codigo":"1002","nombre":"SUBSIDIO X MATERNIDAD"},
    {"id":"208","codigo":"1003","nombre":"ASIGNACI\u00d3N FAMILIAR"},
    {"id":"209","codigo":"9034","nombre":"REM AFE AFP"}],"o170":[{"id":"659","codigo":"001","nombre":"ALGARROBO PAMPEANO"},
{"id":"660","codigo":"002001","nombre":"INDIRECTOS FUNDO AP"}]}

Any idea what I'm doing wrong?