title: why spring boot yaml have to be called application.yml or it can not load successfully
body: <p>I want to map yml data to Map object. Below is my yml data(<code>wikiuser.yml</code>)</p>
  
  <pre><code>spring:
      profiles: default
  
  server: 
      wikiuser: 
          foo: foo@bar.com
  </code></pre>
  
  <p>below is Config object</p>
  
  <pre><code>@Component
  @ConfigurationProperties(prefix="server",locations="wikiuser.yml")
  public class WikiUserConfig {
      private HashMap&lt;String, String&gt; wikiuser;
      //...... 
  }
  </code></pre>
  
  <p>When start my project, it throws NullPointException, because <code>wikiuser</code> is null. </p>
  
  <p>Now changed <code>wikiuser.yml</code> to <code>application.yml</code> , everything is ok！ Why have to be named <code>application</code> even I have specified another name(<code>locations="wikiuser.yml"</code>) explicitly?</p>