java - Adding a keylistener to main() not working -

i'm making game in java ball moves forward no user control, user can control vertical movement of ball, using , down arrow keys, i'm stuck on adding keylistener class/whatever jframe, through main method. basically, add(keylistener_class/method), , java (quite rightly), complains class or method not component. question, then, how supposed add keylistener jframe?

cheers, matt

code:

     package org.ultraluminous.vertiball;
  import java.awt.color; import java.awt.graphics; import java.awt.graphics2d; import java.awt.renderinghints; import java.awt.event.keyevent; import java.awt.event.keylistener; import javax.swing.jframe; import javax.swing.jpanel;  public class game extends jpanel{     static int x = 0;     static int y = 0;     static int ys = 0;  private static void shift(){     x+=1;     y+=ys;     }  public static void event(keyevent e){     if(e.getkeycode() == keyevent.vk_up){         ys = 1;     }     if (e.getkeycode() == keyevent.vk_down){         ys = -1;     } }  public class key{ public void listen() {     keylistener listener = new keylistener() {         @override         public void keytyped(keyevent e) {         }          @override         public void keypressed(keyevent e) {         }          @override         public void keyreleased(keyevent e) {         }     };     addkeylistener(listener);     setfocusable(true); } }        @override     public void paint(graphics g){         super.paint(g);         graphics2d graph = (graphics2d) g;         graph.setrenderinghint(renderinghints.key_antialiasing,          renderinghints.value_antialias_on);         graph.setcolor(color.blue);         graph.drawoval(x, y, 50, 50);         graph.filloval(x, y, 50, 50);     }      public static void main (string[] args){         jframe win = new jframe("pong");             game game = new game();             win.add(new game());             //win.add... add what? need add key listener here                 //but seem unable to.             win.setresizable(false);             win.setsize(900, 600);             win.setdefaultcloseoperation(jframe.exit_on_close);             win.setvisible(true);             while (true) {                 shift();                 win.repaint();                 try {                     thread.sleep(10);                 } catch (interruptedexception e){                     e.printstacktrace();                 }             }        } 

i got work adding keylistener jframe. alternatively create separate class keylistener , add way (instead of using anonymous inner class). here added:

public static void main (string[] args){         jframe win = new jframe("pong");             game game = new game();             win.add(new game());             win.addkeylistener(new keylistener() {                  @override                 public void keytyped(keyevent e) {                 }                  @override                 public void keypressed(keyevent e) {                     if(e.getkeycode() == keyevent.vk_up){                         ys = -1;                     }                     if (e.getkeycode() == keyevent.vk_down){                         ys = 1;                     }                 }                  @override                 public void keyreleased(keyevent e) {                 }              });             win.setresizable(false);             win.setsize(900, 600);             win.setdefaultcloseoperation(jframe.exit_on_close);             win.setvisible(true);             while (true) {                 shift();                 win.repaint();                 try {                     thread.sleep(10);                 } catch (interruptedexception e){                     e.printstacktrace();                 }             }          } }