Custom Adapter generates Null Point Exceptions

Question

So this is actually an update to my previous (now deleted) subpar post about the custom adapter-for some reason it thinks I'm generating null object references for it and won't work as a result.

These are the components of my project:

DBHelper-supplementary section:

package com.myapplicationdev.android.songdbmanager;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

import androidx.annotation.Nullable;

import java.util.ArrayList;


public class DBHelper extends SQLiteOpenHelper {    // Start version with 1
    // increment by 1 whenever db schema changes.
    private static final int DATABASE_VER = 1;
    private static final String TABLE_SONG = "song";
    private static final String COLUMN_ID = "id";
    private static final String COLUMN_TITLE = "title";
    private static final String COLUMN_SINGERS = "singers";
    private static final String COLUMN_YEAR="year";
    private static final String COLUMN_STARS="stars";
    // Filename of the database
    private static final String DATABASE_NAME = "songs.db";

    public DBHelper(@Nullable Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VER);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String dropTableSql = "DROP TABLE IF EXISTS " + TABLE_SONG;
        db.execSQL(dropTableSql);
        String createTableSql = "CREATE TABLE " + TABLE_SONG +  "("
                + COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT,"
                + COLUMN_TITLE + " TEXT,"
                + COLUMN_SINGERS+ " TEXT ,"
                + COLUMN_YEAR + " INTEGER ,"
                + COLUMN_STARS+ " INTEGER )";
        db.execSQL(createTableSql);
        Log.i("info" ,"created tables");


    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // Drop older table if existed
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_SONG);
        // Create table(s) again
        onCreate(db);


    }
    public void insertSong(String title, String singers, int year, int stars){

        // Get an instance of the database for writing
        SQLiteDatabase db = this.getWritableDatabase();
        // We use ContentValues object to store the values for
        //  the db operation
        ContentValues values = new ContentValues();
        // Store the column name as key and the description as value
        values.put(COLUMN_TITLE, title);
        values.put(COLUMN_SINGERS, singers);
        values.put(COLUMN_YEAR, year);
        values.put(COLUMN_STARS, stars);

        // Store the column name as key and the date as value

        // Insert the row into the TABLE_TASK
       db.insert(TABLE_SONG, null, values);
        // Close the database connection
        db.close();
    }
    public ArrayList<song> getAllSongs() {
        ArrayList<song> songlist = new ArrayList<>();

        SQLiteDatabase db = this.getReadableDatabase();

        String[] columns= {COLUMN_ID, COLUMN_TITLE, COLUMN_SINGERS,COLUMN_YEAR,COLUMN_STARS};

        Cursor cursor = db.query(TABLE_SONG, columns, null, null,
                null, null, null, null);

        if (cursor.moveToFirst()) {
            do {
                int id = cursor.getInt(0);
                String title=cursor.getString(1);
                String singers = cursor.getString(2);
                int year=cursor.getInt(3);
                int stars=cursor.getInt(4);
                song Song = new song(id,title,singers,year,stars);
                songlist.add(Song);
            } while (cursor.moveToNext());
        }
        cursor.close();
        db.close();
        return songlist;
    }
    public ArrayList<song> getBestSongs() {
        ArrayList<song> bestsonglist = new ArrayList<>();

        SQLiteDatabase db = this.getReadableDatabase();

        String[] columns= {COLUMN_ID, COLUMN_TITLE, COLUMN_SINGERS,COLUMN_YEAR,COLUMN_STARS};
        String condition = COLUMN_STARS + "= ?";
        String[] args = {"5"};
        Cursor cursor = db.query(TABLE_SONG, columns, condition, args,
                null, null, null, null);

        if (cursor.moveToFirst()) {
            do {
                int id = cursor.getInt(0);
                String title=cursor.getString(1);
                String singers = cursor.getString(2);
                int year=cursor.getInt(3);
                int stars=cursor.getInt(4);
                song Song = new song(id,title,singers,year,stars);
                bestsonglist.add(Song);
            } while (cursor.moveToNext());
        }
        cursor.close();
        db.close();
        return bestsonglist;
    }
    public int updateSong(song Song) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(COLUMN_TITLE, Song.getTitle());
        values.put(COLUMN_SINGERS, Song.getSingers());
        values.put(COLUMN_YEAR, Song.getYear());
        values.put(COLUMN_STARS, Song.getStars());
        String whereClause = COLUMN_ID + "=?";
        String[] whereArgs = {String.valueOf(Song.getId())};
        int result=db.update(TABLE_SONG, values, whereClause, whereArgs);

        if (result < 1) {
            Log.d("DBHelper", "Update failed");

            db.close();
            return result;
        }


        return result;
    }
    public void deleteSong(int songId) {
        SQLiteDatabase db = this.getWritableDatabase();
        String whereClause = COLUMN_ID + "=?";
        String[] whereArgs = {String.valueOf(songId)};
       db.delete(TABLE_SONG, whereClause, whereArgs);
       db.close();
    }}

MainActivity-where the initial processing is done:

package com.myapplicationdev.android.songdbmanager;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.ToggleButton;

import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {

    Button btnInsert, btnGetSongs;
    TextView tvResults;

    EditText YearInput;
    EditText SongInput;
    EditText SingerInput;
    RadioGroup RadioGroupRating;



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

        btnInsert = findViewById(R.id.btnInsert);
        btnGetSongs = findViewById(R.id.btnGetTasks);
        //List View->
        YearInput=findViewById(R.id.insertYear);
        SongInput=findViewById(R.id.insertTitle);
        SingerInput=findViewById(R.id.insertSingers);
        RadioGroupRating=findViewById(R.id.radio_group);


        btnInsert.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                DBHelper db = new DBHelper(MainActivity.this);
                String title=SongInput.getText().toString();
                String singers=SingerInput.getText().toString();
                int year=Integer.parseInt(YearInput.getText().toString());

                int selectedRatingId=RadioGroupRating.getCheckedRadioButtonId();
                RadioButton selectedRatingButton=findViewById(selectedRatingId);
                int rating=Integer.parseInt(selectedRatingButton.getText().toString());
                db.insertSong(title,singers,year,rating);

                SongInput.setText("");
                SingerInput.setText("");
                YearInput.setText("");
                RadioGroupRating.clearCheck();
            }
        });

        btnGetSongs.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                // Create the DBHelper object, passing in the
                // activity's Context

                // Insert a task
                Intent intent = new Intent(MainActivity.this, EditActivity.class);
                //Label the actual editactivity EditActivity2
                startActivity(intent);


            }
        });
    }



}

EditActivity:Where the list is displayed:

{
    ListView lv;
    ArrayList<song> songsList;
    //ArrayAdapter<song> adapter;
    CustomAdapter adapter;
    Button fivestarsongs;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_edit);

        lv = findViewById(R.id.list_view);
        fivestarsongs = findViewById(R.id.btnShow5starsongs);
        DBHelper db = new DBHelper(EditActivity.this);
        songsList = db.getAllSongs();

        //ArrayAdapter<song> adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, songs);

        if (songsList != null && !songsList.isEmpty()) {
            adapter = new CustomAdapter(this, android.R.layout.simple_list_item_1, songsList); // Remove the CustomAdapter declaration here
            lv.setAdapter(adapter);
        }

        fivestarsongs.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ArrayList<song> BestSongs = db.getBestSongs();
                adapter.clear();
                adapter.addAll(BestSongs);
                adapter.notifyDataSetChanged();
            }
        });
        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int
                    position, long id) {
                song ClickedSong = songsList.get(position);
                Intent i = new Intent(EditActivity.this,
                        MainActivity2.class);
                i.putExtra("song", ClickedSong);
                startActivity(i);
            }
        });
    }

}

MainActivity2-supposed to handle delete/update:

package com.myapplicationdev.android.songdbmanager;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.RadioGroup;


public class MainActivity2 extends AppCompatActivity {

    Button btnUpdate,btnCancel,btnDelete;
    EditText YearInput;
    EditText SongInput;
    EditText SingerInput;
    RadioGroup RadioGroupRating;

    song selectedSong;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        DBHelper db = new DBHelper(MainActivity2.this);
        Intent intent = getIntent();
        song clickedSong = (song) intent.getSerializableExtra("song");

        btnUpdate=findViewById(R.id.btnupdate);
        btnCancel=findViewById(R.id.btnCancel);
        btnDelete=findViewById(R.id.btndelete);
        YearInput=findViewById(R.id.insertYear);
        SongInput=findViewById(R.id.insertTitle);
        SingerInput=findViewById(R.id.insertSingers);

        RadioGroupRating=findViewById(R.id.radio_group);

        selectedSong = clickedSong;
        YearInput.setText(String.valueOf(clickedSong.getYear()));
        SongInput.setText(clickedSong.getTitle());
        SingerInput.setText(clickedSong.getSingers());
        setStarsSelection(selectedSong.getStars());


        btnUpdate.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                selectedSong.setTitle(SongInput.getText().toString());
                selectedSong.setSingers(SingerInput.getText().toString());
                selectedSong.setYear(Integer.parseInt(YearInput.getText().toString()));
                selectedSong.setStars(getSelectedStars());
                db.updateSong(selectedSong);
                db.close();
                finish();
            }
        });
        btnDelete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                db.deleteSong(selectedSong.getId());
                db.close();
                finish();
            }
        });
        btnCancel.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity2.this, MainActivity.class);
                startActivity(intent);
                finish();
            }
        });


}

    private int getSelectedStars() {
        int selectedId = RadioGroupRating.getCheckedRadioButtonId();
        RadioButton rbSelected = findViewById(selectedId);
        return Integer.parseInt(rbSelected.getText().toString());
    }
    private void setStarsSelection(int stars) {
        int radioButtonId = 0;
        switch (stars) {
            case 1:
                radioButtonId = R.id.radio_1;
                break;
            case 2:
                radioButtonId = R.id.radio_2;
                break;
            case 3:
                radioButtonId = R.id.radio_3;
                break;
            case 4:
                radioButtonId = R.id.radio_4;
                break;
            case 5:
                radioButtonId = R.id.radio_5;
                break;
        }
        RadioGroupRating.check(radioButtonId);
    }


    }

Song-class involved in all this:

package com.myapplicationdev.android.songdbmanager;

import androidx.annotation.NonNull;

import java.io.Serializable;

public class song implements Serializable {
    private int id;
    private String title;
    private String singers;
    private int year;
    private int stars;


    public void setSingers(String singers) {
        this.singers = singers;
    }

    public void setStars(int stars) {
        this.stars = stars;
    }

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

    public void setYear(int year) {
        this.year = year;
    }

    public song (
                 String title,
                 String singers,
                 int year,
                 int stars
    ){
        this.title=title;
        this.singers=singers;
        this.year=year;
        this.stars=stars;
    }
    public song (
            int id,
            String title,
            String singers,
            int year,
            int stars
    ){
        this.id=id;
        this.title=title;
        this.singers=singers;
        this.year=year;
        this.stars=stars;
    }
    public String getTitle() {
        return title;
    }
    public int getId(){
        return id;
    }

    public int getYear() {
        return year;
    }

    public int getStars() {
        return stars;
    }

    public String getSingers() {
        return singers;
    }


    @NonNull
    @Override
    public String toString() {
        return
                "title='" + title + '\'' +
                ", singers='" + singers + '\'' +
                ", year=" + year +
                ", stars=" + stars
               ;
    }
}

CustomAdapter:

public class CustomAdapter extends ArrayAdapter {
    private Context context;
    private int layoutResourceId;
    private ArrayList<song> songList;

    public CustomAdapter(Context context, int resource, ArrayList<song> objects) {
        super(context, resource, objects);
        this.context = context;
        this.layoutResourceId = resource;
        this.songList = objects;
    }

    @NonNull
    @Override
    public View getView(int position, View rowView, ViewGroup parent) {
        if (rowView == null) {
            LayoutInflater inflater = LayoutInflater.from(context);
            rowView = inflater.inflate(layoutResourceId, parent, false);
        }

        song currentSong = songList.get(position);

        TextView yearInput = rowView.findViewById(R.id.insertYear);
        TextView singerInput = rowView.findViewById(R.id.insertSingers);
        TextView titleInput = rowView.findViewById(R.id.insertTitle);
        RadioGroup radioGroupRating =rowView.findViewById(R.id.radio_group);

        titleInput.setText(currentSong.getTitle());
        singerInput.setText(currentSong.getSingers());
        yearInput.setText(String.valueOf(currentSong.getYear()));

        int selectedValue = currentSong.getStars();
        int radioButtonId = 0;
        switch (selectedValue) {
            case 1:
                radioButtonId = R.id.radio_1;
                break;
            case 2:
                radioButtonId = R.id.radio_2;
                break;
            case 3:
                radioButtonId = R.id.radio_3;
                break;
            case 4:
                radioButtonId = R.id.radio_4;
                break;
            case 5:
                radioButtonId = R.id.radio_5;
                break;
        }
        radioGroupRating.check(radioButtonId);

        return rowView;


}}

And here's the error message associated with these (I'd share the full stack but the text limit likely won't allow me):

It refers to the line where I set the year in the adapter, which is otherwise working as intended.

FATAL EXCEPTION: main
                                                                                                    Process: com.myapplicationdev.android.songdbmanager, PID: 27730
                                                                                                    java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
                                                                                                        at com.myapplicationdev.android.songdbmanager.CustomAdapter.getView(CustomAdapter.java:44)
                                                                                                        at android.widget.AbsListView.obtainView(AbsListView.java:2387)
                                                                                                        at android.widget.ListView.makeAndAddView(ListView.java:2067)
                                                                                                        at android.widget.ListView.fillDown(ListView.java:793)
                                                                                                        at android.widget.ListView.fillFromTop(ListView.java:855)
                                                                                                        at android.widget.ListView.layoutChildren(ListView.java:1838)
                                                                                                        at android.widget.AbsListView.onLayout(AbsListView.java:2184)
                                                                                                        at android.view.View.layout(View.java:22844)
                                                                                                        at android.view.ViewGroup.layout(ViewGroup.java:6389)
                                                                                                        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
                                                                                                        at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1818)
                                                                                                        at android.widget.LinearLayout.onLayout(LinearLayout.java:1584)
                                                                                                        at android.view.View.layout(View.java:22844)
                                                                                                        at android.view.ViewGroup.layout(ViewGroup.java:6389)
                                                                                                        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
                                                                                                        at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
                                                                                                        at android.view.View.layout(View.java:22844)
                                                                                                        at android.view.ViewGroup.layout(ViewGroup.java:6389)
                                                                                                        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
                                                                                                        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
                                                                                                        at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
                                                                                                        at android.view.View.layout(View.java:22844)
                                                                                                        at android.view.ViewGroup.layout(ViewGroup.java:6389)
                                                                                                        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
                                                                                                        at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
                                                                                                        at android.view.View.layout(View.java:22844)
                                                                                                        at android.view.ViewGroup.layout(ViewGroup.java:6389)
                                                                                                        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
                                                                                                        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
                                                                                                        at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
                                                                                                        at android.view.View.layout(View.java:22844)
                                                                                                        at android.view.ViewGroup.layout(ViewGroup.java:6389)
                                                                                                        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
                                                                                                        at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
                                                                                                        at com.android.internal.policy.DecorView.onLayout(DecorView.java:784)
                                                                                                        at android.view.View.layout(View.java:22844)
                                                                                                        at android.view.ViewGroup.layout(ViewGroup.java:6389)
                                                                                                        at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:3470)
                                                                                                        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2938)
                                                                                                        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1952)
                                                                                                        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:8171)
                                                                                                        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:972)
                                                                                                        at android.view.Choreographer.doCallbacks(Choreographer.java:796)
                                                                                                        at android.view.Choreographer.doFrame(Choreographer.java:731)
                                                                                                        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:957)
                                                                                                        at android.os.Handler.handleCallback(Handler.java:938)
                                                                                                        at android.os.Handler.dispatchMessage(Handler.java:99)
                                                                                                        at android.os.Looper.loop(Looper.java:223)
                                                                                                        at android.app.ActivityThread.main(ActivityThread.java:7656)
                                                                                                        at java.lang.reflect.Method.invoke(Native Method)
                                                                                                        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
                                                                                                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

I tried editing the code to check for nulls and even making an object just to check if that's causing the glitch.

Neither of them had much of an effect.