How a clean lib/main.dart should look

main.dart

import 'package:flutter/material.dart';

void main() {
 runApp(Application());
}

class Application extends StatelessWidget {
 @override
 Widget build(BuildContext context) {
   return MaterialApp(
     title: "Admob test",
     home: Scaffold(
       appBar: AppBar(
         title: Text("Flutter admob test"),
       ),
       body: Container(),
     ),
   );
 }
}