title: How to get the 3 highest values in a HashMap?
body: <p>I have a hashmap which is the following:</p>
  
  <pre><code>    HashMap&lt;String, Integer&gt; hm = new HashMap&lt;String, Integer&gt;;
      hm.put("a", 1);
      hm.put("b", 12);
      hm.put("c", 53);
      hm.put("d", 2);
      hm.put("e", 17);
      hm.put("f", 8);
      hm.put("g", 8);
  </code></pre>
  
  <p>How would I get the keys which have the 3 highest values? So it would return:</p>
  
  <pre><code>    "c", "e", "b"
  </code></pre>
  
  <p>Thanks.</p>