Модернизация Android - GoogleBooksAPI - проблема возврата JSON

Question

Я пытаюсь заставить мое приложение для Android возвращать информацию о книге с помощью API книги Google. Вот URL, который я пингую Я использую модификацию, чтобы получить информацию и вернуть ее мне, однако она возвращается вот так, и я не уверен, как ее решить:

D/MainActivity2: onResponse: Success
    onResponse: success body: models.Book2@ae8dded
    onResponse: success response: Response{protocol=h2, code=200, message=, url=https://www.googleapis.com/books/v1/volumes?q=enders+game}
    onResponse: success raw: Response{protocol=h2, code=200, message=, url=https://www.googleapis.com/books/v1/volumes?q=enders+game}
    onResponse: success code: 200
D/MainActivity2: onResponse: success getItems: [models.Book2$Items@b12e422, models.Book2$Items@cd9aeb3, models.Book2$Items@d5c1c70, models.Book2$Items@f826be9, models.Book2$Items@69f206e, models.Book2$Items@b6830f, models.Book2$Items@63e8f9c, models.Book2$Items@70cdda5, models.Book2$Items@ea0d57a, models.Book2$Items@1e2412b]

вот кодовый блок, который я использую для захвата:

    private void parseJson3(String key){
        // source = https://medium.com/@wkrzywiec/making-use-of-open-rest-api-with-retrofit-dac6094f0522
        //  youtube tutorial here: https://www.youtube.com/watch?v=4JGvDUlfk7Y


        JsonPlaceHolderApi serviceEndPoint = ServiceGenerator.createService(JsonPlaceHolderApi.class);



        Call<Book2> call = serviceEndPoint.getQueryItems2("volumes?q=enders+game");
//        Call<Book2Items> call = serviceEndPoint.getQueryItems("volumes?q=enders+game");
//        Call<Book2List> call = serviceEndPoint.getQuery2("volumes?q=enders+game");
//        Call<BookList> call = serviceEndPoint.getQuery1("enders+game");


        call.enqueue(new Callback<Book2>() {
            @Override
            public void onResponse(Call<Book2> call, retrofit2.Response<Book2> response) {

                if (response.isSuccessful()) {

                    String title ="";
//                List<String> author = "";
                    String author =" ";
                    String publishedDate = "Not Available";
                    String publisher = "Not Available";
                    String description = "No Description";
                    int pageCount = 1000;
                    String category = "No categories Available ";
                    String buy ="";
//                String volumeInfoString = "";
                    String bookJSONString = null;
                    String thumbnail = "";
                    String previewLink = "";
                    String price = "";
                    String url = "";


//                for (int i = 0; i < grantResults.length; i++) {
                    for (int i = 0; i < response.body().getItems().size(); i++) {


                        Log.d(TAG, "onResponse: success getmTitle: " + response.body().getItems().get(i).getVolumeInfo().getmTitle());
                        title = response.body().getItems().get(i).getVolumeInfo().getmTitle();
                        Log.d(TAG, "onResponse: success getmAuthors: " + response.body().getItems().get(i).getVolumeInfo().getmAuthors());
//                    author = response.body().getItems().get(i).getVolumeInfo().getmAuthors();
                        Log.d(TAG, "onResponse: success getmCategories: " + response.body().getItems().get(i).getVolumeInfo().getmCategories());
//                    category = response.body().getItems().get(i).getVolumeInfo().getmCategories();
                        Log.d(TAG, "onResponse: success getmDescription: " + response.body().getItems().get(i).getVolumeInfo().getmDescription());
                        description = response.body().getItems().get(i).getVolumeInfo().getmDescription();
                        Log.d(TAG, "onResponse: success getmPublisher: " + response.body().getItems().get(i).getVolumeInfo().getmPublisher());
                        publisher = response.body().getItems().get(i).getVolumeInfo().getmPublisher();
                        Log.d(TAG, "onResponse: success getmImageLinks: " + response.body().getItems().get(i).getVolumeInfo().getmImageLinks().getmThumbnail());
                        thumbnail = response.body().getItems().get(i).getVolumeInfo().getmImageLinks().getmThumbnail();
                    }

                    Log.d(TAG, "onResponse: title = " + title);


                    mBooks.add(new Book2(title, author, publishedDate, description ,category
                            , thumbnail, buy, previewLink, price, pageCount, url));


                    mSearchViewRecyclerViewAdapter = new SearchViewRecyclerViewAdapter(MainActivity2.this , mBooks);
                    mRecyclerView.setAdapter(mSearchViewRecyclerViewAdapter);

                } else {

                    Log.d(TAG, "onResponse: call in MainActivity2 was not successful");
                }
            }

            @Override
            public void onFailure(Call<Book2> call, Throwable t) {

                Log.d(TAG, "onFailure: didnt work" + t);
            }
        });
    }

вот моя Book2 модель с геттерами и сеттерами:

    public class Book2 {

    @SerializedName("items")
    private List<Items> items;

    public Book2() {
        // no arg constructor needed
    }

    public Book2(Items items) {

    }

    public List<Items> getItems() {
        return items;
    }

    public void setItems(List<Items> items) {
        this.items = items;
    }

    public class Items {

        @SerializedName("volumeInfo")
        private VolumeInfo volumeInfo;


        public VolumeInfo getVolumeInfo() {
            return volumeInfo;
        }

        public void setVolumeInfo(VolumeInfo volumeInfo) {
            this.volumeInfo = volumeInfo;
        }
    }


    public class VolumeInfo {

        @SerializedName("title")
        private String mTitle;

        @SerializedName("authors")
        private ArrayList<String> mAuthors;

        @SerializedName("publisher")
        private String mPublisher;

        @SerializedName("publishedDate")
        private String mPublishedDate;

        @SerializedName("description")
        private String mDescription;

//        @SerializedName("industryIdentifiers")
//        private ArrayList<String> mIndustryIdentifiers;

        @SerializedName("categories")
        private ArrayList<String> mCategories;

        @SerializedName("imageLinks")
        private ImageLinks mImageLinks;




        public String getmTitle() {
            return mTitle;
        }

        public void setmTitle(String mTitle) {
            this.mTitle = mTitle;
        }

        public ArrayList<String> getmAuthors() {
            return mAuthors;
        }

        public void setmAuthors(ArrayList<String> mAuthors) {
            this.mAuthors = mAuthors;
        }

        public String getmPublisher() {
            return mPublisher;
        }

        public void setmPublisher(String mPublisher) {
            this.mPublisher = mPublisher;
        }

        public String getmPublishedDate() {
            return mPublishedDate;
        }

        public void setmPublishedDate(String mPublishedDate) {
            this.mPublishedDate = mPublishedDate;
        }

        public String getmDescription() {
            return mDescription;
        }

        public void setmDescription(String mDescription) {
            this.mDescription = mDescription;
        }

/*
        public ArrayList<String> getmIndustryIdentifiers() {
            return mIndustryIdentifiers;
        }

        public void setmIndustryIdentifiers(ArrayList<String> mIndustryIdentifiers) {
            this.mIndustryIdentifiers = mIndustryIdentifiers;
        }

 */

        public ArrayList<String> getmCategories() {
            return mCategories;
        }

        public void setmCategories(ArrayList<String> mCategories) {
            this.mCategories = mCategories;
        }


        public ImageLinks getmImageLinks() {
            return mImageLinks;
        }

        public void setmImageLinks(ImageLinks mImageLinks) {
            this.mImageLinks = mImageLinks;
        }
    }

    public class ImageLinks {
        @SerializedName("thumbnail")
        private String mThumbnail;

        public String getmThumbnail() {
            return mThumbnail;
        }

        public void setmThumbnail(String mThumbnail) {
            this.mThumbnail = mThumbnail;
        }
    }


}

MainActivity2

public class MainActivity2 extends AppCompatActivity {


    private RecyclerView mRecyclerView;
    private ArrayList<Book2> mBooks;
    private SearchViewRecyclerViewAdapter mSearchViewRecyclerViewAdapter;
    private RequestQueue mRequestQueue;

    private static  final  String BASE_URL2="https://www.googleapis.com/books/v1/";
    private static  final  String BASE_URL_TYPICODE="https://jsonplaceholder.typicode.com/";
//    private static  final  String BASE_URL="https://www.googleapis.com/books/v1/volumes?q=";


    private EditText search_edit_text;
    Button search_button;
    ProgressBar loading_indicator;
    private TextView error_message;

//    private static final String LOG_TAG = MainActivity2.class.getSimpleName();
    private static final String TAG = "MainActivity2";



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_book_main2);

        search_edit_text=findViewById(R.id.search_box);
        search_button= findViewById(R.id.search_buttton);
        loading_indicator=findViewById(R.id.loading_indicator);
        error_message= findViewById(R.id.message_display);

        mRecyclerView = findViewById(R.id.recycler_view);
        mRecyclerView.setHasFixedSize(true);
        mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
        mBooks = new ArrayList<>();
        mRequestQueue = Volley.newRequestQueue(this);


        search_button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mBooks.clear();
                search();
            }
        });
    }

   private void parseJson3(String key){
        // source = https://medium.com/@wkrzywiec/making-use-of-open-rest-api-with-retrofit-dac6094f0522
        //  youtube tutorial here: https://www.youtube.com/watch?v=4JGvDUlfk7Y


        JsonPlaceHolderApi serviceEndPoint = ServiceGenerator.createService(JsonPlaceHolderApi.class);



        Call<Book2> call = serviceEndPoint.getQueryItems2("volumes?q=enders+game");
//        Call<Book2Items> call = serviceEndPoint.getQueryItems("volumes?q=enders+game");
//        Call<Book2List> call = serviceEndPoint.getQuery2("volumes?q=enders+game");
//        Call<BookList> call = serviceEndPoint.getQuery1("enders+game");


        call.enqueue(new Callback<Book2>() {
            @Override
            public void onResponse(Call<Book2> call, retrofit2.Response<Book2> response) {

                if (response.isSuccessful()) {

                    String title ="";
//                List<String> author = "";
                    String author =" ";
                    String publishedDate = "Not Available";
                    String publisher = "Not Available";
                    String description = "No Description";
                    int pageCount = 1000;
                    String category = "No categories Available ";
                    String buy ="";
//                String volumeInfoString = "";
                    String bookJSONString = null;
                    String thumbnail = "";
                    String previewLink = "";
                    String price = "";
                    String url = "";


//                for (int i = 0; i < grantResults.length; i++) {
                    for (int i = 0; i < response.body().getItems().size(); i++) {


                        Log.d(TAG, "onResponse: success getmTitle: " + response.body().getItems().get(i).getVolumeInfo().getmTitle());
                        title = response.body().getItems().get(i).getVolumeInfo().getmTitle();
                        Log.d(TAG, "onResponse: success getmAuthors: " + response.body().getItems().get(i).getVolumeInfo().getmAuthors());
//                    author = response.body().getItems().get(i).getVolumeInfo().getmAuthors();
                        Log.d(TAG, "onResponse: success getmCategories: " + response.body().getItems().get(i).getVolumeInfo().getmCategories());
//                    category = response.body().getItems().get(i).getVolumeInfo().getmCategories();
                        Log.d(TAG, "onResponse: success getmDescription: " + response.body().getItems().get(i).getVolumeInfo().getmDescription());
                        description = response.body().getItems().get(i).getVolumeInfo().getmDescription();
                        Log.d(TAG, "onResponse: success getmPublisher: " + response.body().getItems().get(i).getVolumeInfo().getmPublisher());
                        publisher = response.body().getItems().get(i).getVolumeInfo().getmPublisher();
                        Log.d(TAG, "onResponse: success getmImageLinks: " + response.body().getItems().get(i).getVolumeInfo().getmImageLinks().getmThumbnail());
                        thumbnail = response.body().getItems().get(i).getVolumeInfo().getmImageLinks().getmThumbnail();
                    }

                    Log.d(TAG, "onResponse: title = " + title);


//                    mBooks.add(new Book2(title, author, publishedDate, description ,category
//                            , thumbnail, buy, previewLink, price, pageCount, url));

                    mBooks.add(new Book2());


                    mSearchViewRecyclerViewAdapter = new SearchViewRecyclerViewAdapter(MainActivity2.this , mBooks);
                    mRecyclerView.setAdapter(mSearchViewRecyclerViewAdapter);

                } else {

                    Log.d(TAG, "onResponse: call in MainActivity2 was not successful");
                }
            }

            @Override
            public void onFailure(Call<Book2> call, Throwable t) {

                Log.d(TAG, "onFailure: didnt work" + t);
            }
        });
    }

private boolean Read_network_state(Context context)
    {    boolean is_connected;
        ConnectivityManager cm =(ConnectivityManager) context.getSystemService(CONNECTIVITY_SERVICE);
        NetworkInfo info = cm.getActiveNetworkInfo();
        is_connected=info!=null&&info.isConnectedOrConnecting();
        return is_connected;
    }


    private void search()
    {
        String search_query = search_edit_text.getText().toString();

        boolean is_connected = Read_network_state(this);
        if(!is_connected)
        {
            error_message.setText(R.string.Failed_to_Load_data);
            mRecyclerView.setVisibility(View.INVISIBLE);
            error_message.setVisibility(View.VISIBLE);
            return;
        }

        //  Log.d("QUERY",search_query);


        if(search_query.equals(""))
        {
            Toast.makeText(this,"Please enter your query",Toast.LENGTH_SHORT).show();
            return;
        }
        String final_query=search_query.replace(" ","+");

        Uri uri=Uri.parse(BASE_URL2+final_query);
//        Uri uri=Uri.parse(BASE_URL+final_query);
        Uri.Builder buider = uri.buildUpon();

        parseJson3(buider.toString());


    }


}

SearchViewRecyclerViewAdapter.java

public class SearchViewRecyclerViewAdapter extends RecyclerView.Adapter<SearchViewRecyclerViewAdapter.MyViewHolder> {

    private Context mContext;
    private List<Book2> mData;
    private RequestOptions options;
    private static final String LOG_TAG = SearchViewRecyclerViewAdapter.class.getSimpleName();


    public SearchViewRecyclerViewAdapter(Context mContext, List<Book2> mData) {
        this.mContext = mContext;
        this.mData = mData;

        //Request option for Glide
        options = new RequestOptions().centerCrop().placeholder(R.drawable.loading_shape).error(R.drawable.loading_shape);
    }

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int i) {

        View view;
        LayoutInflater inflater = LayoutInflater.from(mContext);
        view = inflater.inflate(R.layout.book_raw_item2 , parent , false);
        final MyViewHolder viewHolder =  new MyViewHolder(view);
        viewHolder.container.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i = new Intent(mContext , BookProfileActivity2.class);
                int pos = viewHolder.getAdapterPosition();
//                i.putExtra("book_title" ,mData.get(pos).getTitle());
                i.putExtra("book_author" ,mData.get(pos).getAuthors());
//                i.putExtra("book_desc" ,mData.get(pos).getDescription());
                i.putExtra("book_categories" ,mData.get(pos).getCategories());
                i.putExtra("book_publish_date" ,mData.get(pos).getPublishedDate());
                i.putExtra("book_info" ,mData.get(pos).getmUrl());
                i.putExtra("book_buy" ,mData.get(pos).getBuy());
                i.putExtra("book_preview" ,mData.get(pos).getPerview());
                i.putExtra("book_thumbnail" ,mData.get(pos).getThumbnail());
//                i.putExtra("volumeInfo" ,mData.get(pos).getVolumeInfo());

//                Log.d(LOG_TAG, "onClick: " + mData.get(pos).getVolumeInfo());


                mContext.startActivity(i);
            }
        });
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder, int i) {

        Book2 book = mData.get(i);
//        holder.tvTitle.setText(book.getTitle());
        holder.tvAuthor.setText(book.getAuthors());
        holder.tvPrice.setText(book.getPrice());
        holder.tvCategory.setText(book.getCategories());

        //load image from internet and set it into imageView using Glide
        Glide.with(mContext).load(book.getThumbnail()).apply(options).into(holder.ivThumbnail);

    }

    @Override
    public int getItemCount() {
        return mData.size();
    }

    public static class MyViewHolder extends RecyclerView.ViewHolder{

        ImageView ivThumbnail ;
        TextView tvTitle , tvCategory , tvPrice , tvAuthor;
        LinearLayout container ;
        public MyViewHolder(@NonNull View itemView) {
            super(itemView);

            ivThumbnail = itemView.findViewById(R.id.thumbnail);
            tvTitle = itemView.findViewById(R.id.title);
            tvAuthor = itemView.findViewById(R.id.author);
            tvCategory = itemView.findViewById(R.id.category);
            tvPrice = itemView.findViewById(R.id.price);
            container = itemView.findViewById(R.id.container);


        }
    }
}

любая помощь и направление приветствуется. если вы выбрали downvote, укажите причину.