PaintComponent method doesn't display anything on JLabel?

Question

I am trying to show a histogram for a image in jlabel, but its not working.
//hist : array containing histogram values
//wid: width of image
//ht: height of image
mylabel.add(new showData(hist,wid,ht));
The code that I am using to display histogram is:
class showData extends JLabel{
int w,h;
int hist[] = new int[256];
int max_hist=0;
public showData(int[] histValue,int w, int h) {
System.arraycopy(histValue, 0, hist, 0, 256);
this.w = w;
this.h = h;
for (int i = 0; i < 256; i++) {
if(hist>max_hist)
max_hist=hist[i];
@Override
protected void paintComponent(Graphics g)
super.paintComponent(g);
int x = (w - 256) / 2;
int lasty = h - h * hist[0] / max_hist;
for (int i=0; i<256; i++, x++) {
int y = h - h * hist[i] / max_hist;
g.setColor(new Color(i, i, i));
g.fillRect(x, y, 1, h);
g.setColor(Color.red);
g.drawLine(x-1,lasty,x,y);
lasty = y;
When debugged, I found that showData() method was getting invoked, but paintComponent() doesn't. Why is it so? The Jlabel 'mylabel' doesn't show anything?

Answer 1

Check size and location of the JLabel. If size 0 the paintComponent() is not called. Try to set preferred size to the label.