title: Why is there no direct implemention of Bag in java collection framework?
body: <p>I can't figure out why JCF (Java Collection Framework) does't have a <code>Bag</code> implementation(to allow duplicates and not maintain order).
  <code>Bag</code> performance would be much better than current Collection implementations in JCF.</p>
  
  <ul>
  <li>I know how to implement <code>Bag</code> in Java.</li>
  <li>I know <code>Bag</code> is available in Apache commons.</li>
  <li>I know there are other implementations that can be used as a <code>Bag</code> but there is so much work to do in other implementations compared to a <code>Bag</code>.</li>
  </ul>
  
  <p>Why has the Java Collections framework not provided direct implementations like this?</p>