title: Java ArrayList of Integer[], how to access elements
body: <p>I am using an ArrayList of  to create lists.
  For example:</p>
  
  <pre><code>Index 0: 1 3
  Index 1: 4 5
  Index 2: 1 3 7
  </code></pre>
  
  <p>How can I access the second element of the first index of the ArrayList? Couldn't find the answer on Google, so I asked here.</p>