Iterable< ? extends iface_class >
<p>I am new to Java. Can someone tell me what does it mean by this line?</p>

<pre><code>class_A
...
Iterable&lt; ? extends iface_classB&gt; getThings();
</code></pre>

<p>where iface_classB can be either interface/abstract of classB here.</p>

<p>i got the error when i write something as:</p>

<pre><code>class_A myA = new classA()

Iterable&lt; impl_of_iface_classB &gt; anIterator = myA.getThings()
</code></pre>

<p>I wonder about question mark inside the template. My guess was that it should be anything that derive from <code>iface_classB</code> but it seems i was wrong.</p>

<p>Thank you very much for any answer.</p>
