title: Add an object to an ArrayList and modify it later
body: <p>If I have an ArrayList, and I added an object to it, and later I modified this object, will this change reflect in the ArrayList? or when I add the object to the ArrayList, Java creates a copy and add it to the ArrayList?</p>
  
  <p>What if I change the reference to this object to null? Does that mean that the object in the ArrayList now null too?</p>