title: How to add and retrieve the values in Arraylist of ArrayList
body: <p>I know how to <strong>create</strong> an <code>ArrayList</code> of <code>ArrayList</code>, but how to <strong>add</strong> new <code>ArrayList</code> and <strong>add</strong> value to that particular <code>ArrayList</code> and how to <strong>retrieve</strong> the data from that list.</p>
  
  <pre><code>ArrayList&lt;ArrayList&lt;Integer&gt;&gt; arrayList = new ArrayList&lt;ArrayList&lt;Integer&gt;&gt;();
  </code></pre>