color box in java

import java.awt.Graphics;
 import java.awt.Color;

 public class ColorBoxes extends java.applet.Applet {

public void paint(Graphics g) {
 int rval, gval, bval;

 for (int j = 30; j < (this.size().height -25); j += 30)
 for (int i = 5; i < (this.size().width -25); i+= 30) {
 rval = (int)Math.floor(Math.random() * 256);
 gval = (int)Math.floor(Math.random() * 256);
 bval = (int)Math.floor(Math.random() * 256);

 g.setColor(new Color(rval,gval,bval));
 g.fillRect(i,j,25,25);
 g.setColor(Color.black);
 g.drawRect(i-1,j-1,25,25);
 }
 }
 }