swing - Java JComponent doesn't refresh -

i've got problem class component. problem ovals doesn't changing colors. function if observing ovf flag in class counter. when ovf=true ovals should red, , when ovf=false ovals should white. in gui can see red ovals (even if ovf=false). try add repaint() command red ovals started blinking. here code:

import java.awt.*; import javax.swing.*; import java.util.observable;   public class komponent extends jcomponent { counter counter3; public komponent() {     counter3=new counter(); } public void paint(graphics g)  {  graphics2d dioda = (graphics2d)g;  int x1 = 85;  int x2 = 135;  int y = 3;  int width = (getsize().width/9)-6;  int height = (getsize().height-1)-6;   if (counter3.ovf = true)  {  dioda.setcolor(color.red);  dioda.filloval(x1, y, width, height);  dioda.filloval(x2, y, width, height);  } if (counter3.ovf = false) {  dioda.setcolor(color.white);  dioda.filloval(x1, y, width, height);  dioda.filloval(x2, y, width, height); } } public static void main(string[] arg) {  new komponent(); } } 

what wrong code?

if should be:

if (counter3.ovf == true) { // watch out = , ==     // red } if (counter3.ovf == false) {     // white } 

or simpler:

if (counter3.ovf) {     // red } else {     // white } 

or simplest:

dioda.setcolor(counter3.ovf ? color.red : color.white); dioda.filloval(x1, y, width, height); dioda.filloval(x2, y, width, height);