title: What does super.paintComponent(g) do?
body: <p>What does <code>super.paintComponent(g)</code> do (especially when we place it inside paintComponent() method)? I am surprised I don't see anyone asking this in SO before.</p>
  
  <p>I dig out my school notes on Java Graphics, the only thing it mentioned on this line of code is <code>"do not delete"</code>.</p>
  
  <p>However I have been practicing and tying out on Java paintComponent() method these few weeks. So far I have not included that line into my codes, and everything seems to work well (so far). So..</p>
  
  <p><strong>Questions:</strong></p>
  
  <ol>
  <li>What does it do?</li>
  <li>When do we need to use it?</li>
  <li>What advantage does it gives us by writing it in paintComponent()?</li>
  </ol>