@Autowired vs @Required on setter

Question

I\'m curious to know what\'s the difference between code like this:

class MyClass {
   @Autowired
   MyService myService;
}

and code like t

Answer 1

@watchme @Required -annotation tells to the container that this property needs to be initialized as part of configuration, it can be initialized either through xml configuration or through @Autowired annotation or through java bean creation.

1. xml example:

   public class SimpleMovieLister 
   { 
    private MovieFinder movieFinder;
   
    @Required
    public void setMovieFinder(MovieFinder movieFinder)
    {
       this.movieFinder = movieFinder;
    }
   }
   
   
   
   
   
    
   

1. through @Autowire

   public class SimpleMovieLister 
   { 
     @Autowired 
     @Required
     private MovieFinder movieFinder;
   }
   
   

Here truly speaking we don't need @Required as it @Autowired default is Required.

3. thru @Bean

   public class SimpleMovieLister 
   { 
     private MovieFinder movieFinder;
   
     @Required
     public void setMovieFinder(MovieFinder movieFinder)
     {
        this.movieFinder = movieFinder;
     }
   }
   
   
   public class AppConfig {
   
   @Bean
   public SimpleMovieLister getSimpleMovieLister()
   {
      SimpleMovieLister simpleMovieLister = new SimpleMovieLister();
      simpleMovieLister.setMovieFinder(new MoveFinder());
   }
   }