public void setAccess (ArrayList<RestAccess> rr) {
    restaccess = rr;
}


public ArrayList<RestAccess> getAccess () {
    return restaccess;
}

public void setExpDate (String expdate){
    this.expiration_date = expdate;
}


public String getExpDate() {
    return this.expiration_date;
};

public static void main(String[] args) throws FileNotFoundException, IOException {
    // TODO code application logic here
    String fpath = "C:\BPMINST\json.txt";

    String json_str = "";
    BufferedReader bufferedReader = null;
    bufferedReader = new BufferedReader(new FileReader(fpath));
    String sCurrentLine;
    while ((sCurrentLine = bufferedReader.readLine()) != null) {
        json_str = json_str + sCurrentLine;
    }
    System.out.println(json_str);
    Gson gson = new Gson();
    CollectionAccess orderHeader = gson.fromJson(json_str, CollectionAccess.class);
    if (orderHeader==null){
        System.out.println("orderHeader is null");
        return;
    } else {
        System.out.println("orderHeader not  is null");
    };
    ArrayList<RestAccess> orderDetailList = orderHeader.getAccess();
    if (orderDetailList!=null){
         System.out.println(orderDetailList.size());
    };
}