When I press key noting happen. Why ?

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

class Oknoextends JFrame{

Ekran e =new Ekran();

Container cp = getContentPane();

//cp.add(e);

public Okno(){

setTitle("Okienko");

setSize(500,350);

setLocation(200,100);

setResizable(false);

cp.add(e);

}

}

class Ekranextends JPanelimplements KeyListener{

int x=100;

int y=100;

public Ekran(){

addKeyListener(this);

}

publicvoid paintComponent(Graphics g){

g.drawOval(x,y,50,50);

}

publicvoid keyTyped(KeyEvent evt){}

publicvoid keyReleased(KeyEvent evt){}

publicvoid keyPressed(KeyEvent evt){

int z=evt.getKeyCode();

if (z==KeyEvent.VK_UP){

x+=20;

y+=20;

repaint();

}

}

}

publicclass Gra{

publicstaticvoid main(String[] args){

Okno o =new Okno();

o.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

o.show();

}

}

[2705 byte] By [Thunder22a] at [2007-10-2 1:23:38]