title: How to change a value of a field in an ArrayList of objects?
body: <p>I know how to add an object:</p>
  
  <pre><code>ArrayList&lt;Object&gt; ob = new ArrayList&lt;Object&gt;();
  
  ob.add (index, some_object);
  </code></pre>
  
  <p>But let say the object has a field called 'name', how can I change that single field only?<br>
  For example:</p>
  
  <pre><code>ob.setName(name); 
  </code></pre>
  
  <p>(I know this does not work.)</p>