run time permission

package com.example.teachingdemoapp;

import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import android.Manifest;
import android.accounts.Account;
import android.accounts.AccountManager;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity  {

    String TAG = "MainActivity";

    int permission = 13;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (checkPermissions()){
                Toast.makeText(this, "all permissions given", Toast.LENGTH_SHORT).show();
            }else {
                Toast.makeText(this, "give permissions", Toast.LENGTH_SHORT).show();
            }
        }

    }

    @RequiresApi(api = Build.VERSION_CODES.M)
    boolean checkPermissions(){
        int cameraPermission = checkSelfPermission(Manifest.permission.CAMERA);
        int smsPermission = checkSelfPermission(Manifest.permission.READ_SMS);

        List<String> permissionsList = new ArrayList<>();

        if (cameraPermission != PackageManager.PERMISSION_GRANTED){
            permissionsList.add(Manifest.permission.CAMERA);
        }

        if (smsPermission != PackageManager.PERMISSION_GRANTED){
            permissionsList.add(Manifest.permission.READ_SMS);
        }

        if (permissionsList.size() > 0){
            requestPermissions(permissionsList.toArray(new String[permissionsList.size()]),permission);
            return false;
        }

        return true;
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {

        if(requestCode == permission && grantResults.length == 2){
            Toast.makeText(this, "granted all permissions", Toast.LENGTH_SHORT).show();
        }
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }
}