IntentService

@Override
    protected void onHandleIntent(Intent intent) {
        Log.d(this.getClass().getName(), "New intent received.");
        BookProvider bookProvider = new BookProvider();
        bookProvider.setContext(this);
        String url = this.getResources().getString(R.string.api_url) + "books";

        InputStream source = retrieveStream(url);
        StringWriter writer = new StringWriter();
        String retrievedJSON = "";
        if (source != null) {
            try {
                IOUtils.copy(source, writer);
                retrievedJSON = writer.toString();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        if (!retrievedJSON.equals("")) {
            Gson gson = new Gson();
            BookListEntry[] bookListEntries = gson.fromJson(retrievedJSON, BookListEntry[].class);

            for (BookListEntry bookListEntry : bookListEntries) {
                ContentValues contentValues = new ContentValues();
                contentValues.put(BookOpenHelper.BOOK_ID, bookListEntry.bookId);
                contentValues.put(BookOpenHelper.BOOK_TITLE, bookListEntry.bookTitle);
                contentValues.put(BookOpenHelper.BOOK_ISBN, bookListEntry.bookISBN);
                contentValues.put(BookOpenHelper.BOOK_PRICE, bookListEntry.bookPrice);
                contentValues.put(BookOpenHelper.BOOK_AUTHOR, bookListEntry.bookAuthor);
                bookProvider.insert(BookProvider.CONTENT_URI, contentValues);
            }
        }
    }
}