title: How to append a string to a HashMap element?
body: <p>I have a hashmap in java and I need to append a string to one specific key. Is this code correct ? Or it is not a good practice to invoke .get method to retrieve the original content ?</p>
  
  <pre><code>myMap.put("key", myMap.get("key") + "new content") ;
  </code></pre>
  
  <p>thanks</p>