In a java swing game, the animation itself does not work. why?

Question

Java

I am writing a simple swing game, I am learning it, so to speak, the essence of the matter is:
my animation only works if I somehow expand or vice versa reduce the window frame. otherwise nothing happens, what to do?
https://github.com/DeadSidert/myGame

Answer 1

I forgot to call repaint() in move();