title: What is the point of Collection<?>
body: <p>I have been reading Effective Java and I have come across the unbounded Collection type <code>&lt;?&gt;</code>. However, the reading has led me to believe that you can't put any elements, other than <code>null</code>, into an instance of <code>Collection&lt;?&gt;</code>.</p>
  
  <p>So, my question is this: what is the purpose of instantiating a <code>Collection&lt;?&gt;</code> when we can only insert <code>null</code> elements as it seems pointless. I've been trying to figure out this concept, but it just doesn't seems to make much sense. Any help would be much appreciated.</p>