In your code you draw only one polygone.
Thread.sleep causes the main
thread (Event Dispatch Thread, EDT) to sleep, in that half of second the application hangs.
And even if it draws that first polygon before call to move() the super.painComponent(g) will clear that and then it draws that polygon after move()...
Maybe you could call move() in painComponent(Graphics) method... and for the second polygone create a new GeneralPath.
Debugging is
finding bugs