//Jsp (server)

    String xCatalogo = request.getParameter("xCatalogo");
    String xdburl = request.getParameter("xUrl");
    String xdbuser = request.getParameter("xUser");
    String xdbpass = request.getParameter("xPass");
    conexion con = new conexion(xdburl, xdbuser, xdbpass);
    ResultSet rs1;
    int xResultado = 0;
    JSONObject json = new JSONObject();
    String qry = "";
    String whtml2 = "";
  //  ArrayList<String> catalog = new ArrayList<String>();
    if (xCatalogo.equals("cFrigorificos")) {
        qry = "select * from tcatfrigo where icatfrigostatus=1 order by icatfrigoorden";
        rs1 = con.consulta(qry);
        List<catFrigorifico> listacatFrigorificos =  new ArrayList<catFrigorifico>();
        if (rs1.next()) {
            xResultado = 1;
            rs1.beforeFirst();
            while (rs1.next()) {
                catFrigorifico xFrigo = new catFrigorifico(rs1.getInt("icatfrigoid"), rs1.getString("ccatfrigocodigo"), rs1.getString("ccatfrigonombre"), rs1.getInt("icatfrigoorden"));
                listacatFrigorificos.add(xFrigo);
//                catalog.add(rs1.getInt("icatfrigoid") + "|" + rs1.getString("ccatfrigocodigo") + "|" + rs1.getString("ccatfrigonombre") + "|" + rs1.getInt("icatfrigoorden"));
            }
        }
//        json.put("xListaCatalogosFrigorificos", catalog);
        json.put("xListaCatalogosFrigorificos", listacatFrigorificos);
    }
    json.put("xResultado", xResultado);
    out.println(json);
    out.flush();

//Android (client)
try {
                    //Creating JsonObject from response String
                    JSONObject jsonObject = new JSONObject(response.toString());
                    Log.v("JSONParser", "response: " + response.toString());
                    //extracting json array from response string
                    JSONArray jsonArray = jsonObject.getJSONArray("xListaCatalogosFrigorificos");
                    for (int i=0; i<jsonArray.length(); i++){
                            JSONObject json_data = jsonArray.getJSONObject(i);
                        json_data = json_data;
                    }
                } catch (JSONException e) {
                    Log.i("tag", "error Json " + e.getMessage());
                }


the problem is in Android Part in this line:
 JSONObject json_data = jsonArray.getJSONObject(i);

throw a exception and is:
"Value beans.catFrigorifico@15aa13f7 at 0 of type java.lang.String cannot be converted to JSONObject"

how to fix?