title: Is there analog Collections.singleton() / Collections.singletonList() / Collections.singletonMap() to obtain mutable collection?
body: <p>I know if I have element and I want to get <code>List</code>/<code>Set</code>/<code>Map</code> with this element I can invoke :</p>
  
  <p><code>Collections.singleton()</code> /  <code>Collections.singletonList()</code> / <code>Collections.singletonMap()</code></p>
  
  <p>At this case I get immutable collection(I cannot add/delete element to collection).</p>
  
  <p>Is there analog to obtain mutable collection?</p>