AsyncTask class for stackoverflow question : https://stackoverflow.com/questions/63176435/activity-does-not-respond-and-recyclerview-not-reflecting-changes

private static class ReadDbTableAllAsyncTask extends AsyncTask<ArrayList<String>, Void, ArrayList<String>>{
    private static final String TAG = "[MY_DEBUG]";

        private WeakReference<MainActivity> activityWeakReference;
        private SQLiteDatabase db1;
        private long milli_seconds = 0;
        private Calendar calendar = Calendar.getInstance();
        private DateFormat formatter = new SimpleDateFormat("dd/MM/yyyy h:mm a");
        private String printable_date;
        private int i=0;
        private  ArrayList<String> messages_list = new ArrayList();
        private  Cursor cursor_read_from_table_all;
        private int progress_iterator;
        private boolean cursor_first;

    ReadDbTableAllAsyncTask(MainActivity activity, SQLiteDatabase db2){
            activityWeakReference = new WeakReference<MainActivity>(activity);
            db1 = db2;
            i=0;
    }

        @Override
        protected ArrayList<String> doInBackground(ArrayList<String>... arrayList) {
            db1.beginTransaction();
            String[] projection = {
                    BaseColumns._ID,
                    SpamBusterContract.TABLE_ALL.COLUMN_CORRES_INBOX_ID,
                    SpamBusterContract.TABLE_ALL.COLUMN_SMS_BODY,
                    SpamBusterContract.TABLE_ALL.COLUMN_SMS_ADDRESS,
                    SpamBusterContract.TABLE_ALL.COLUMN_SMS_EPOCH_DATE
            };

            String selection = null;
            String[] selectionArgs = null;

            String sortOrder =
                    SpamBusterContract.TABLE_ALL.COLUMN_SMS_EPOCH_DATE + " desc ";   //latest one appears on top of array_adapter


            cursor_read_from_table_all = db1.query(
                    SpamBusterContract.TABLE_ALL.TABLE_NAME,   // The table to query
                    projection,             // The array of columns to return (pass null to get all)
                    selection,              // The columns for the WHERE clause
                    selectionArgs,          // The values for the WHERE clause
                    null,                   // don't group the rows
                    null,                   // don't filter by row groups
                    sortOrder               // The sort order
            );

            i = 0;
            cursor_first = cursor_read_from_table_all.moveToFirst();
            if (!cursor_first) {
                Log.d(TAG, "ReadDbTableAllAsyncTask: doInBackground(): TABLE_ALL is empty");
            }
            else {
                Log.d(TAG, "ReadDbTableAllAsyncTask doInBackground: interator i = " + i);
                int index_id = cursor_read_from_table_all.getColumnIndexOrThrow(SpamBusterContract.TABLE_ALL._ID);
                int index_corres_id = cursor_read_from_table_all.getColumnIndexOrThrow(SpamBusterContract.TABLE_ALL.COLUMN_CORRES_INBOX_ID);
                int index_sms_body = cursor_read_from_table_all.getColumnIndexOrThrow(SpamBusterContract.TABLE_ALL.COLUMN_SMS_BODY);
                int index_sms_address = cursor_read_from_table_all.getColumnIndexOrThrow(SpamBusterContract.TABLE_ALL.COLUMN_SMS_ADDRESS);
                int index_sms_epoch_date = cursor_read_from_table_all.getColumnIndexOrThrow(SpamBusterContract.TABLE_ALL.COLUMN_SMS_EPOCH_DATE);
                try {
                    messages_list.clear();
                    do {
                        long itemId = cursor_read_from_table_all.getLong(index_id);
                        String corress_inbox_id = cursor_read_from_table_all.getString(index_corres_id);
                        String sms_body = cursor_read_from_table_all.getString(index_sms_body);
                        String sms_address = cursor_read_from_table_all.getString(index_sms_address);
                        String epoch_date = cursor_read_from_table_all.getString(index_sms_epoch_date);
                        Log.d(TAG, " doInBackground() : itemId = " + itemId);
                        Log.d(TAG, " doInBackground() :  corress_inbox_id = " + corress_inbox_id);
                        Log.d(TAG, " doInBackground() : sms_body = " + sms_body);
                        Log.d(TAG, " doInBackground() : sms_address = " + sms_address);
                        milli_seconds = Long.parseLong(epoch_date);
                        calendar.setTimeInMillis(milli_seconds);
                        printable_date = formatter.format(calendar.getTime());
                        Log.d(TAG, " doInBackground() : epoch_date = " + epoch_date + " which is : " + printable_date);
                        Log.d(TAG, " doInBackground() : ");
                        String str = "ItemID = " + itemId + "\ncorress_inbox_id = " + corress_inbox_id + "\n SMS From: " + getContactName(activityWeakReference.get(), sms_address) + "\n Recieved at: " + printable_date + "\n" + sms_body;
                        Log.d(TAG, "doInBackground: progress_iterator = " + progress_iterator);
                        Log.d(TAG, "doInBackground: i = " + i);
                        Log.d(TAG, "doInBackground: adding into message_list at index + " + progress_iterator);
                        Log.d(TAG, "doInBackground: messages_list.add(" + progress_iterator + ", " + str + ")");
                        messages_list.add(progress_iterator++, str);
                        Log.d(TAG, "ReadDbTableAllAsyncTask doInBackground: incrementing iterator i to " + ++i);
                    } while (cursor_read_from_table_all.moveToNext());
                }
                catch(Exception e){
                    Log.d(TAG, "doInBackground: exception : " + e);
                }
            }
            cursor_read_from_table_all.close();
            return messages_list;
        }

        @Override
        protected void onPreExecute() {
            super.onPreExecute();

            MainActivity activity = activityWeakReference.get();
            if (activity == null || activity.isFinishing()) {
                return;
            }
            messages_list.clear();
        }

        @Override
        protected void onPostExecute(ArrayList<String> msg_list) {
            super.onPostExecute(msg_list);
            MainActivity activity = activityWeakReference.get();
            if (activity == null || activity.isFinishing()) {
                return;
            }
            int j=0;
            try {
                    while (j < msg_list.size()) {
                    activity.sms_adapter.insert(j, msg_list.get(j).toString());
                        activity.sms_adapter.notifyDataSetChanged();
                    j++;
                }
            }
            catch (Exception e){
                Log.d(TAG, "onPostExecute: exception : " + e);
            }
            Log.d(TAG, "onPostExecute: Finished reading TABLE_ALL");
            activity.messages.setAdapter(activity.sms_adapter);
            activity.messages.setLayoutManager(new LinearLayoutManager(activity));
            db1.startTransaction();
            db1.close();
        }
}