title: why not Map#removeAll(Collection<?>)?
body: <p>Why doesn't the <code>Map</code> interface in Java have a <code>removeAll(Collection&lt;?&gt; c)</code> method to remove keys, like it has <code>map.remove(Object)</code>?</p>
  
  <p>I know I can always do <code>map.keySet().removeAll(..)</code> .. but is this a reason that <code>Map</code> doesn't have <code>removeAll()</code> and encourages us to go with <code>map.keySet().removeAll(..)</code> ?</p>