title: Improve if containsKey in map by java 8 interface
body: <p>I've got entity/form called Time with fields:</p>
  
  <pre><code>Integer id;
  Date date;
  Integer value;
  </code></pre>
  
  <p>And another form called SummaryForm</p>
  
  <pre><code>String title;
  String descr;
  List&lt;Object&gt; newList;
  </code></pre>
  
  <p>How to improve map usage with Java 8 interface.
  Right now I've got an if statement:</p>
  
  <pre><code>if (map.containsKey(key)) {
              map.get(key).newList().add(new SummaryForm(time.getDate(), time.getValue()));
          }
  </code></pre>
  
  <p>Is there any simple way to improve it to avoid if statements, t with map.containsKey?
  In my opinion, I need something like putIfPresent, but it seems there is an only putIfAbsent method.</p>