title: Getting the difference between two sets
body: <p>So if I have two sets:</p>
  
  <pre><code>Set&lt;Integer&gt; test1 = new HashSet&lt;Integer&gt;();
  test1.add(1);
  test1.add(2);
  test1.add(3);
  
  Set&lt;Integer&gt; test2 = new HashSet&lt;Integer&gt;();
  test2.add(1);
  test2.add(2);
  test2.add(3);
  test2.add(4);
  test2.add(5);
  </code></pre>
  
  <p>Is there a way to compare them and only have a set of 4 and 5 returned?</p>