title: Java Observer Update function
body: <p>I have a class that implements observer, and of course it needs to have the update function:</p>
  
  <pre><code>public void update(Observable obs, Object obj);
  </code></pre>
  
  <p>Can someone please explain what do the two parameters stand for?
  Observable is my observable of course, but, how can I access my observable fields through this Observable obs object?
  And what is Object obj?</p>