Application that uses Alert Dialog Box

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Close App"
        android:layout_centerInParent="true"/>

</RelativeLayout>

package com.example.myapplication;

import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {
    Button closeButton;
    AlertDialog.Builder builder;

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

        closeButton = findViewById(R.id.btn);

        closeButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                builder = new AlertDialog.Builder(MainActivity.this).setTitle("Alert Dialog Example")
                        .setMessage("Do you want to close this application ?")
                        .setCancelable(false)
                        .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialogInterface, int i) {
                                Toast.makeText(MainActivity.this, "You choose yes action", Toast.LENGTH_SHORT).show();
                                finish();
                            }
                        }).setNegativeButton("No", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialogInterface, int i) {
                                Toast.makeText(MainActivity.this, "You choose no action", Toast.LENGTH_SHORT).show();
                                dialogInterface.dismiss();
                            }
                        });
                builder.show();
            }
        });
    }

}