title: is there a way to have a "main" arraylist?
body: <p>Let's say I have</p>
  <pre><code>ArrayList&lt;Citizen&gt; citizen1 = new ArrayList&lt;Citizen&gt;();
  ArrayList&lt;Citizen&gt; citizen2 = new ArrayList&lt;Citizen&gt;();
  ArrayList&lt;Citizen&gt; citizen3 = new ArrayList&lt;Citizen&gt;();
  </code></pre>
  <p>is it possible to have an arraylist which compromise them all?</p>