title: Why parameter of contains() of list class differ from containAll()?
body: <p>Hi I checked Params of Contains methods and ContainsAll method .</p>
  
  <pre><code>boolean containsAll(Collection&lt;?&gt; c);
  
  boolean contains(Object o);
  </code></pre>
  
  <p>It seems both will accept Object . Is there any difference among two.</p>