title: How to properly get a Collection out of an Entity using getProperty()
body: <p>When I put an ArrayList into an Entity using setUnindexedProperty(), how does it come back out?</p>
  
  <p>I'm doing this:</p>
  
  <pre><code>Collection&lt;Key&gt; keys = (Collection&lt;Key&gt;) entity.getProperty(propName);
  </code></pre>
  
  <p>And I get this warning:</p>
  
  <pre><code> warning: [unchecked] unchecked cast
  found   : java.lang.Object
  required: java.util.Collection&lt;com.google.appengine.api.datastore.Key&gt;
      Collection&lt;Key&gt; keys = (Collection&lt;Key&gt;) entity.getProperty(propName);
  </code></pre>
  
  <p>Is this the best I can do?  Is there at least a way to get rid of the warning?</p>
  
  <p>UPDATE: I do not get this warning on other entity.getProperty() calls that return an object that I downcast to, say a String or a Blob.</p>