Make HTTP request and parse JSON data from Android by using HttpURLConnection

BooksActivity.java

//The original sample is from here: http://syntx.io/how-to-send-an-http-request-from-android-using-httpurlconnection/
//Deprecated funcitons and non-working code are modeifed.  
//For more reference, please visit: http://developer.android.com/reference/java/net/HttpURLConnection.html
//I am using Google Books APIs for this sample. 
//The returned book objects might have different format according to the language/country. (The second book obejct in data.json is the Japanese version)

    //execute the AsyncTask some place in the UI thread 
    //new CatalogClient().execute("https://www.googleapis.com/books/v1/mylibrary/bookshelves/3/volumes?country=US");
        
        
    public class CatalogClient extends AsyncTask<String, String, List<Book>> {
        @Override
        protected List<Book> doInBackground(String... params) {
            URL url;
            HttpURLConnection urlConnection = null;
            List<Book> books= new ArrayList<>();
            
            try {
                url = new URL(params[0]);
                urlConnection = (HttpURLConnection) url.openConnection();
                urlConnection.setRequestMethod("GET");
                //HTTP header
                urlConnection.setRequestProperty("Authorization", "Bearer "+ token);

                int responseCode = urlConnection.getResponseCode();
                String responseMessage = urlConnection.getResponseMessage();

                if(responseCode == HttpURLConnection.HTTP_OK){
                    String responseString = readStream(urlConnection.getInputStream());
                    Log.v("CatalogClient-Response", responseString);
                    books = parseBookData(responseString);
                }else{
                    Log.v("CatalogClient", "Response code:"+ responseCode);
                    Log.v("CatalogClient", "Response message:"+ responseMessage);
                }

            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if(urlConnection != null)
                    urlConnection.disconnect();
            }

           
            return books;
        }

        private String readStream(InputStream in) {
            BufferedReader reader = null;
            StringBuffer response = new StringBuffer();
            try {
                reader = new BufferedReader(new InputStreamReader(in));
                String line = "";
                while ((line = reader.readLine()) != null) {
                    response.append(line);
                }
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                if (reader != null) {
                    try {
                        reader.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
            return response.toString();
        }


        private List<Book> parseBookData(String jString){

            List<Book> bookList = new ArrayList<Book>();
            try {
                JSONObject jObj = new JSONObject(jString);
                String totalItems= jObj.getString("totalItems");
                Log.v("totalItems",totalItems);
                if (Integer.parseInt(totalItems) == 0) {
                    ((TextView) findViewById(R.id.JSON_value)).setText("You have no books in this shelf");
                } else {
                    JSONArray items = jObj.getJSONArray("items");
                    if(items != null) {
                        for (int i = 0; i < items.length(); i++) {
                            String title = items.getJSONObject(i).getJSONObject("volumeInfo").getString("title");
                            String picURL = items.getJSONObject(i).getJSONObject("volumeInfo").getJSONObject("imageLinks").getString("thumbnail");
                            String isbn = items.getJSONObject(i).getJSONObject("volumeInfo").getJSONArray("industryIdentifiers").getJSONObject(1).getString("identifier");
                            //the value of progress is a placeholder here....
                            Book book = new Book(title, picURL, isbn, 0);
                            bookList.add(book);
                            Log.v("bookList", "Title "+ title + "thumbnail "+ picURL + "isbn " + isbn);
                        }

                    }

                }

            } catch (JSONException e) {
                Log.e("CatalogClient", "unexpected JSON exception", e);
            }

            return bookList;
        }






        protected void onPostExecute(List<Book> books) {
            super.onPostExecute(books);
            //make use of data..


        }
    }

Book.java

public class Book {
    private String title;
    private String picURL;
    private String isbn;
    private double progress;

    public Book(String title, String picURL, String isbn, double progress){
        this.title = title;
        this.picURL = picURL;
        this.isbn = isbn;
        this.progress = progress;
    }


    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getPicURL() {
        return picURL;
    }

    public void setPicURL(String picURL) {
        this.picURL = picURL;
    }

    public String getIsbn() {
        return isbn;
    }

    public double getProgress() {
        return progress;
    }
}

data.json

{
  "kind": "books#volumes",
  "totalItems": 2,
  "items": [
    {
      "kind": "books#volume",
      "id": "JV6rpwAACAAJ",
      "etag": "7NWBjOkpxiI",
      "selfLink": "https://www.googleapis.com/books/v1/volumes/JV6rpwAACAAJ",
      "volumeInfo": {
        "title": "Node.js in Action",
        "authors": [
          "Mike Cantelon",
          "T. J. Holowaychuk",
          "Marc Harter",
          "Nathan Rajlich"
        ],
        "publisher": "Manning Publications",
        "publishedDate": "2013-07-28",
        "description": "Provides information on using Node.js to build scalable Web applications, covering such topics as asynchronous programming, data storage, and output templating.",
        "industryIdentifiers": [
          {
            "type": "ISBN_10",
            "identifier": "1617290572"
          },
          {
            "type": "ISBN_13",
            "identifier": "9781617290572"
          }
        ],
        "readingModes": {
          "text": false,
          "image": false
        },
        "pageCount": 395,
        "printType": "BOOK",
        "categories": [
          "Computers"
        ],
        "averageRating": 3.5,
        "ratingsCount": 14,
        "maturityRating": "NOT_MATURE",
        "allowAnonLogging": false,
        "contentVersion": "preview-1.0.0",
        "imageLinks": {
          "smallThumbnail": "http://books.google.com/books/content?id=JV6rpwAACAAJ&printsec=frontcover&img=1&zoom=5&source=gbs_api",
          "thumbnail": "http://books.google.com/books/content?id=JV6rpwAACAAJ&printsec=frontcover&img=1&zoom=1&source=gbs_api"
        },
        "previewLink": "http://books.google.com/books?id=JV6rpwAACAAJ&hl=&source=gbs_api",
        "infoLink": "http://books.google.com/books?id=JV6rpwAACAAJ&hl=&source=gbs_api",
        "canonicalVolumeLink": "http://books.google.com/books/about/Node_js_in_Action.html?hl=&id=JV6rpwAACAAJ"
      },
      "userInfo": {
        "updated": "2015-09-22T20:19:42.945Z"
      },
      "saleInfo": {
        "country": "US",
        "saleability": "NOT_FOR_SALE",
        "isEbook": false
      },
      "accessInfo": {
        "country": "US",
        "viewability": "NO_PAGES",
        "embeddable": false,
        "publicDomain": false,
        "textToSpeechPermission": "ALLOWED",
        "epub": {
          "isAvailable": false
        },
        "pdf": {
          "isAvailable": false
        },
        "webReaderLink": "http://books.google.com/books/reader?id=JV6rpwAACAAJ&hl=&printsec=frontcover&output=reader&source=gbs_api",
        "accessViewStatus": "NONE",
        "quoteSharingAllowed": false
      }
    },
    {
      "kind": "books#volume",
      "id": "Y81uAAAACAAJ",
      "etag": "C5B+LugISuU",
      "selfLink": "https://www.googleapis.com/books/v1/volumes/Y81uAAAACAAJ",
      "volumeInfo": {
        "title": "源氏物",
        "subtitle": "全代",
        "authors": [
          "紫式部"
        ],
        "publishedDate": "1978",
        "industryIdentifiers": [
          {
            "type": "ISBN_10",
            "identifier": "4061582275"
          },
          {
            "type": "ISBN_13",
            "identifier": "9784061582279"
          }
        ],
        "readingModes": {
          "text": false,
          "image": false
        },
        "pageCount": 166,
        "printType": "BOOK",
        "maturityRating": "NOT_MATURE",
        "allowAnonLogging": false,
        "contentVersion": "preview-1.0.0",
        "previewLink": "http://books.google.com/books?id=Y81uAAAACAAJ&hl=&source=gbs_api",
        "infoLink": "http://books.google.com/books?id=Y81uAAAACAAJ&hl=&source=gbs_api",
        "canonicalVolumeLink": "http://books.google.com/books/about/%E6%BA%90%E6%B0%8F%E7%89%A9%E8%AA%9E.html?hl=&id=Y81uAAAACAAJ"
      },
      "userInfo": {
        "updated": "2015-09-22T20:19:09.245Z"
      },
      "saleInfo": {
        "country": "US",
        "saleability": "NOT_FOR_SALE",
        "isEbook": false
      },
      "accessInfo": {
        "country": "US",
        "viewability": "NO_PAGES",
        "embeddable": false,
        "publicDomain": false,
        "textToSpeechPermission": "ALLOWED",
        "epub": {
          "isAvailable": false
        },
        "pdf": {
          "isAvailable": false
        },
        "webReaderLink": "http://books.google.com/books/reader?id=Y81uAAAACAAJ&hl=&printsec=frontcover&output=reader&source=gbs_api",
        "accessViewStatus": "NONE",
        "quoteSharingAllowed": false
      }
    }
  ]
}