title: Remove duplicates ArrayList custom object
body: <p>I have an ArrayList which contains element of a class <code>Event</code>.
  Event has two properties, <code>Name</code> and <code>Timestamp</code>.
  The list now shows ALL events.
  I want to remove the duplicates with the same name, but different timestamp, and put them in another list. This way the user can click on an event with that name, then select a date.</p>
  
  <p>I am already overriding the function equals (that compares name AND timestamp) for some other functionalities in my application.</p>
  
  <p>How can I solve this?</p>