title: Add Elements to an ArrayList within a HashMap
body: <p>How to add an Element to an ArrayList within a HashMap?</p>
  
  <p>This is a question, that I have asked myself many times and forgot it after solving it. I guess many have the same one so here is the simple answer to it.</p>
  
  <pre><code>// Example
  HashMap&lt;String, ArrayList&lt;String&gt;&gt; someElements = new HashMap&lt;String, ArrayList&lt;String&gt;&gt;();
  </code></pre>