title: what difference, when using objectify?
body: <p>Ask from <a href="https://github.com/mpxr/Foodely/blob/master/api/src/main/java/hu/iit/bme/api/model/ProfileEndpoint.java" rel="nofollow">here</a>
  what difference between:</p>
  
  <pre><code>Profile profile = ofy().load().type(Profile.class).id(userId).now();
  </code></pre>
  
  <p>and</p>
  
  <pre><code>Profile profile = ofy().load().key(Key.create(Profile.class, userId)).now();
  </code></pre>
  
  <p>why we must create key for userId using <code>Key.create(Profile.class, userId)</code>? 
  Thanks.</p>