public class Point {
  private int x;
  private int y;

  public void move(int x,int y) {
    this.x=x;
    this.y=y;
  }

  @Override public String toString() {
    return "("+x+','+y+')';
  }

  public static void main(String[] args) {
    final Point p=new Point();

    for(int i=0;i<2;i++) {
      final int id=i;
      new Thread(new Runnable() {
        public void run() {
          for(;;) {
            p.move(id,id);
            System.out.println(p);
          }
        }
      }).start();
    }
  }
}