First of all if you want to use threads in main class you must run him in special class called Executorservice. or:
class My thread implements Runnable {your code} (this class must be above yout main class)
then in your main class(in static method main) you wrire something like this : Thread t = new Thresd(new My());t.start();
Second: in hazlo you make Point class and use them to change circle position. Then in your main method in thread class , you create another Point class. POint class in thread isn't invoke your circle point. They are different object.