SQLite connection leaked even when everything is closed

Question

I am getting this error

A SQLiteConnection object for database '/data/data/com.*******/databases/myDatabase' was leaked!  Please fix your application to end transactions in progress properly and to close the database when it is no longer needed.

I closed all cursors and database but I still get this error

This is my Database helper class:

public static DatabaseHelper getInstance(Context ctx) {


        if (mInstance == null) {
            mInstance = new DatabaseHelper(ctx.getApplicationContext());
        }
        return mInstance;
    }
    private DatabaseHelper(Context context) {
        super(context, DB_NAME, null, 1);

        if (android.os.Build.VERSION.SDK_INT >= 17) {
            DB_PATH = context.getApplicationInfo().dataDir + "/databases/";
        } else {
            DB_PATH = "/data/data/" + context.getPackageName() + "/databases/";
        }
        this.context = context;
        ...


    }

 public void create() throws IOException {
        boolean dbExist = checkDataBase();

        if (dbExist) {
            //do nothing - database already exist
        } else {
            this.getReadableDatabase();
            try {
                copyDataBase();
            } catch (IOException e) {
                throw new Error("Error copying database");
            }
        }
    }
private boolean checkDataBase() {

        File dbFile = new File(DB_PATH + DB_NAME);

        return dbFile.exists();
    }

private void copyDataBase() throws IOException {
    InputStream myInput = context.getAssets().open(DB_NAME);
    String outFileName = DB_PATH + DB_NAME;
    OutputStream myOutput = new FileOutputStream(outFileName);
    byte[] buffer = new byte[1024];
    int length;
    while ((length = myInput.read(buffer)) > 0) {
        myOutput.write(buffer, 0, length);
    }

    myOutput.flush();
    myOutput.close();
    myInput.close();
}

public boolean open() {
    try {
        String myPath = DB_PATH + DB_NAME;
        db = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
        return true;
    } catch (SQLException sqle) {
        db = null;
        return false;
    }
}

@Override
public synchronized void close() {
    if (db != null)
        db.close();
    super.close();
}
public List<MyPojo> getCat() {
    List<MyPojo> pojos = new ArrayList<>();

    try {

        String query = "SELECT DISTINCT _id, CatA FROM  Categories ORDER BY _id ASC ";
        SQLiteDatabase db = SQLiteDatabase.openDatabase(DB_PATH + DB_NAME, null, SQLiteDatabase.OPEN_READWRITE);
        Cursor cursor = db.rawQuery(query, null);

        while (cursor.moveToNext()) {
            int catID = cursor.getInt(0);
            String catName = cursor.getString(1);

            MyPojo pojo = new MyPojo(catID, catName);

            pojos.add(pojo);
        }
        cursor.close();
    } catch(Exception e) {
        Log.d("DB", e.getMessage());
    }


    return pojos;
}

and this is how I use them in my code:

private List<MyPojo> getCat() {
        List<MyPojo> pojos = new ArrayList<>();

        DatabaseHelper db = DatabaseHelper.getInstance(getContext());
        try {
            db.create();
        } catch (IOException ioe) {
            throw new Error("Unable to create database");
        }
        try {
            if (db.open()) {
                pojos = db.getCat();
            }
        }finally {
            db.close();
        }
        return pojos;
    }

I have also tried this link but still no luck. I can't seem to find where exactly the leak is happening.

What am I doing wrong?