How does the event dispatch thread work?

Question

With the help of people on stackoverflow I was able to get the following working code of a simple GUI countdown (which just displays a window counting down seconds). My main

Answer 1

You are actually starting the counter thread from the EDT. If you called counter.start() after the invokeLater block, the counter would likely start to run before the GUI becomes visible. Now, because you're constructing the GUI in the EDT, the GUI wouldn't exist when the counter starts to update it. Luckily you seem to be forwarding the GUI updates to the EDT, which is correct, and since the EventQueue is a queue, the first update will happen after the GUI has been constructed, so there should be no reason why this wouldn't work. But what's the point of updating a GUI that may not be visible yet?