events - Java GUI - Moving a circle with no "footprints" -

when run program , move circle, appears if i'm drawing paintbrush in paint. i'm not quite sure did make this, or can make stop. highly appreciated.

here code:

import java.awt.graphics; import java.awt.event.actionlistener; import java.awt.event.actionevent; import java.awt.event.keyevent;  import javax.swing.jframe; import javax.swing.timer; import javax.swing.jpanel; import java.awt.event.keylistener;   public class movingcar extends jpanel implements actionlistener, keylistener {      timer tm = new timer(5, this);     int x = 0, y = 0, velx = 0, vely = 0;      public movingcar()     {         tm.start();         addkeylistener(this);         setfocusable(true);         setfocustraversalkeysenabled(false);     }     protected void paintcomponent (graphics g) {         super.paintcomponents(g);         g.drawoval(x, y, 50, 50);     }      public void actionperformed(actionevent e){         x = x + velx;         y = y + vely;         repaint();     }      public void keypressed(keyevent e){         int c = e.getkeycode();          if (c == keyevent.vk_down)      {             velx = -1;             vely = 0;         }          if (c == keyevent.vk_up)         {             velx = 1;             vely = 0;         }       }        public void keytyped(keyevent e){}     public void keyreleased(keyevent e){          if (x < 0)         {             velx = 0;             x = 0;         }          if (x > 600)         {             velx = 0;             x = 0;         }           repaint();           vely = 0;         velx = 0;      }       public static void main(string[] args) {         movingcar o = new movingcar();         jframe jf = new jframe();         jf.settitle("circle move");         jf.setsize(600,400);         jf.setdefaultcloseoperation(jframe.exit_on_close);         jf.add(o);         jf.setvisible(true);     }   } 

you're calling super.paintcomponents(g); instead of super.paintcomponent(g);