title: Java 8 stream unique Integers
body: <p>Can i reduce the following code to one/two line? </p>
  
  <pre><code>DTO dto;
  List&lt;DTO&gt; dtos;
  List&lt;Integer&gt; list1 = dtos.stream().map(DTO::getFirstId).distinct().collect(Collectors.toList());
  List&lt;Integer&gt; list2 = dtos.stream().map(DTO::getSecondId).distinct().collect(Collectors.toList());
  
  List&lt;Integer&gt; reducedId = list1.stream().filter(list2::contains).collect(Collectors.toList());
  </code></pre>