Need to save nested JSON strings from server to SQLite. How to do?

Question

Java

I receive data like this:

{
    "dur": 50,
    "inter": 600,
    "time_start": 54,
    "time_end": 108,
    "lunch_s": 780,
    "lunch_e": 840,
    "workweek": {
        "1": "Mon",
        "2": "Tue"
    },
    "delay": 150
}

The request body looks like this:

public class BodyUserSettings implements Serializable {

@SerializedName("dur")
@Expose
private String duration;
@SerializedName("inter")
@Expose
private String intervals;
@SerializedName("time_start")
@Expose
private String timeWorkStart;
@SerializedName("time_end")
@Expose
private String timeWorkEnd;
@SerializedName("lunch_s")
@Expose
private String lunchStart;
@SerializedName("lunch_e")
@Expose
private String lunchEnd;
@SerializedName("workweek")
@Expose
private Workweek workweek;
@SerializedName("delay")
@Expose
private String timeDelay;

public String getDuration() {
    return duration;
}

public void setDuration(String duration) {
    this.duration = duration;
}

public BodyUserSettings withDuration(String duration) {
    this.duration = duration;
    return this;
}

public String getIntervals() {
    return intervals;
}

public void setIntervals(String intervals) {
    this.intervals = intervals;
}

public BodyUserSettings withIntervals(String intervals) {
    this.intervals = intervals;
    return this;
}

public String getTimeWorkStart() {
    return timeWorkStart;
}

public void setTimeWorkStart(String timeWorkStart) {
    this.timeWorkStart = timeWorkStart;
}

public BodyUserSettings withTimeWorkStart(String timeWorkStart) {
    this.timeWorkStart = timeWorkStart;
    return this;
}

public String getTimeWorkEnd() {
    return timeWorkEnd;
}

public void setTimeWorkEnd(String timeWorkEnd) {
    this.timeWorkEnd = timeWorkEnd;
}

public BodyUserSettings withTimeWorkEnd(String timeWorkEnd) {
    this.timeWorkEnd = timeWorkEnd;
    return this;
}

public String getLunchStart() {
    return lunchStart;
}

public void setLunchStart(String lunchStart) {
    this.lunchStart = lunchStart;
}

public BodyUserSettings withLunchStart(String lunchStart) {
    this.lunchStart = lunchStart;
    return this;
}

public String getLunchEnd() {
    return lunchEnd;
}

public void setLunchEnd(String lunchEnd) {
    this.lunchEnd = lunchEnd;
}

public BodyUserSettings withLunchEnd(String lunchEnd) {
    this.lunchEnd = lunchEnd;
    return this;
}

public Workweek getWorkweek() {
    return workweek;
}

public void setWorkweek(Workweek workweek) {
    this.workweek = workweek;
}

public BodyUserSettings withWorkweek(Workweek workweek) {
    this.workweek = workweek;
    return this;
}

public String getTimeDelay() {
    return timeDelay;
}

public void setTimeDelay(String timeDelay) {
    this.timeDelay = timeDelay;
}

public BodyUserSettings withTimeDelay(String timeDelay) {
    this.timeDelay = timeDelay;
    return this;
}

public class Workweek implements Serializable {

    @SerializedName("1")
    @Expose
    private String _1;
    @SerializedName("2")
    @Expose
    private String _2;

    public Workweek(String _1, String _2) {
        super();
        this._1 = _1;
        this._2 = _2;
    }

    public String getId() {
        return _1;
    }

    public void setId(String id) {
        this._1 = id;
    }

    public Workweek withId(String _1) {
        this._1 = _1;
        return this;
    }

    public String getTitle() {
        return _2;
    }

    public void setTitle(String _2) {
        this._2 = _2;
    }

    public Workweek withTitle(String _2) {
        this._2 = _2;
        return this;
    }
}
}

POST request:

@POST("/settings")
Call<BodyUserSettings> postIdToken(@Body BodyIdToken id_token);

In mainactivity:

private void sendRequestIdTokenToServer() {
    BodyIdToken hexPost = new BodyIdToken();
    hexPost.idToken = mIdToken;
    Call<BodyUserSettings> call = mService.postIdToken(hexPost);
    call.enqueue(new Callback<BodyUserSettings>() {
        @Override
        public void onResponse(@NonNull Call<BodyUserSettings> call, @NonNull Response<BodyUserSettings> response) {
            mBodyUserSettings = response.body();
            mMainDatabase.saveSettings(mBodyUserSettings);
            mMainDatabase.saveWorkweekDays(mBodyWorkweek);
        }

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

        }
    });
}

Tables in SQLite:

private final String CREATE_SETTINGS_TABLE = "CREATE TABLE IF NOT EXISTS " +
            SETTINGS_TABLE + "(" +
            _id + " INTEGER PRIMARY KEY AUTOINCREMENT," +
            DURATION + "INTEGER," +
            INTERVALS + " INTEGER," +
            TIME_START + " INTEGER," +
            TIME_END + " INTEGER," +
            LAUNCH_S + " INTEGER," +
            LAUNCH_E + " INTEGER," +
            WORKWEEK + " INTEGER," +
            DELAY + " INTEGER" + ")";

    private final String CREATE_WORKWEEK_TABLE = "CREATE TABLE IF NOT EXISTS " +
            WORKWEEK_TABLE + "(" +
            _id + " INTEGER PRIMARY KEY," +
            ID_DAY + " TEXT," +
            TITLE_DAY + " TEXT" + ")";

Saving to SQLite

public void saveSettings(BodyUserSettings settings) {
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues cv = new ContentValues();

    cv.put(DURATION, settings.getDuration());
    cv.put(INTERVALS, settings.getIntervals());
    cv.put(TIME_START, settings.getTimeWorkStart());
    cv.put(TIME_END, settings.getTimeWorkEnd());
    cv.put(LAUNCH_S, settings.getLunchStart());
    cv.put(LAUNCH_E, settings.getLunchEnd());
    cv.put(WORKWEEK, String.valueOf(settings.getWorkweek()));
    cv.put(DELAY, settings.getTimeDelay());

    db.insert(SETTINGS_TABLE, null, cv);
    Log.d("LOG_TAG_saveSettings ", "save: " +
            settings.getDuration() + "; " +
            settings.getIntervals() + "; " +
            settings.getTimeWorkStart() + "; " +
            settings.getTimeWorkEnd() + "; " +
            settings.getLunchStart() + "; " +
            settings.getLunchEnd() + "; " +
            settings.getWorkweek() + "; " +
            settings.getTimeDelay() + ".");
    db.close();
}

public void saveWorkweekDays(BodyUserSettings.Workweek workweek) {
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues cv = new ContentValues();

    cv.put(ID_DAY, workweek.getId());
    cv.put(TITLE_DAY, workweek.getTitle());

    db.insert(WORKWEEK_TABLE, null, cv);
    Log.d("LOG_TAG_saveWorkweek", "save " +
            workweek.getId() + "; " +
            workweek.getTitle() + ".");
    db.close();
}
}

I don’t understand how I can correctly display data from workweek. Maybe they don't save at all. What am I doing wrong?
If you use JSON parsing, then how to do it and then save it in SQLite?