PriorityQueue poll
<p>Looks like PriorityQueue is a LIFO structure (if all the elements in it have same priority), am I right?</p>

<pre><code> public E poll() {
    if (size == 0)
        return null;
    modCount++;

    E result = (E) queue[1];
    queue[1] = queue[size];
    queue[size--] = null;  // Drop extra ref to prevent memory leak
    if (size &gt; 1)
        fixDown(1);

    return result;
}
</code></pre>
