title: How does Spring framework autowire a collection
body: <p>I've never seen an autowired collection:</p>
  
  <pre><code>@Service
  public class SomeFactory {
      @Autowired
      private List&lt;Foo&gt; foos;
  
      @PostConstruct
      public void init() {
          for(Foo foo: foos) { 
              //do something
          }
      }
  }
  </code></pre>
  
  <p>In init() method, I can see foos has several entries already. I guess Spring knows who's supposed to be the entry of foos. But, how? What should I do if I want to add a Foo object into foos? Need to configure in a property file, or any other idea?</p>