title: transform a list of objects into a list of integers that pass a check
body: <p>I would like to get a <code>List</code> of <code>Integer</code>s, in order, having values less than 5.</p>
  
  <p>How can I do it?</p>
  
  <pre><code>TreeMap&lt;String,Object&gt; treeMap = new TreeMap&lt;String,Object&gt;();
  HashMap&lt;String,Object&gt; map1 = new HashMap&lt;String,Object&gt;();
  
  map1.put("a",1);
  map1.put("b","2x");
  map1.put("c",5);
  map1.put("d",3);
  map1.put("e",2);
  
  List&lt;Object&gt; x = new ArrayList&lt;&gt;();
  
  x = map1.values()
         .stream()
         .collect(Collectors.toList());
  
  x.forEach(System.out::println);
  </code></pre>