java - how to implement timer the right way in JFrame -

i struggling find out how point in program change every second or 2 timer. have tried combinations, have been unsuccessful. believe there in actionlistener might have failed on.

arraylist<point> punkter = new arraylist<point>();  int = 0; int n = 0; public point[] point = null; private timer timer; random rg = new random();   public timer(){     this.settitle("draw");     this.setdefaultcloseoperation(jframe.exit_on_close);     this.setsize(1010, 710);     this.setlayout(null);     this.setlocationrelativeto(null);      point = new point[100];      this.setvisible(true);      timer = new timer(500,this);     timer.start(); } public void paint(graphics g){     super.paint(g);      (int = 0; < punkter.size(); i++) {         point = punkter.get(i);         point b = punkter.get((i+1)%punkter.size());         g.filloval(a.x,  a.y, 5, 5);         g.drawline(a.x, a.y, b.x, b.y);     }    } @override public void actionperformed(actionevent e) {     // todo auto-generated method stub     for(int = 0;i < 100;i++){         point[i] = new point(rg.nextint(1000), rg.nextint(700));         punkter.add(point[i]); }     } } 

call repaint() on component when wish repaint, otherwise paintcomponent (or paint) method may not called. possibly not directly related advice worth giving (and noted in comment trashgod): use component added jframe (like jpanel), , perform drawing within paintcomponent method of component (if so, should call repaint on component).