Adding Events - duplication

Hi,

Excuse my inability to figure this out, but I am having trouble with
duplicate Events showing up on my Calendar, and was hoping someone
could offer some advice on how to control for this.

I am using the Java Client Library, and I can successfully add and
delete events from my Calendar. However, I can add the same Event over
and over, with exactly the same info, and it simply re-adds the same
Event to the Calendar. As I will have to program some Calendar
synchronization, I do not want every Event to be re-added every time.

I figure I am missing something, but am dizzy from going in circles.
Any help would be kindly appreciated.

Best,
taivo