title: Adding a value to a list to an already existing key in Map
body: <p>Evening!</p>
  
  <p>I have the following Map:</p>
  
  <pre><code>HashMap&lt;String, ArrayList&gt; myMap = new HashMap&lt;String, ArrayList&gt;();
  </code></pre>
  
  <p>I then added the following data to it:</p>
  
  <pre><code>ArrayList myList = new ArrayList();
  myList.add("Test 1");
  myList.add("Test 2");
  myList.add("Test 3");
  myMap.put("Tests", myList);
  </code></pre>
  
  <p>This left me with the following data:</p>
  
  <p><strong>Key:</strong> Tests</p>
  
  <hr>
  
  <p><strong>Values:</strong> Test 1, Test 2, Test 3</p>
  
  <p>My question is, how do I then add new values on to my already existing key? So for example, how could I add the value "Test 4" onto my key "Tests".</p>
  
  <p>Thanks.</p>