keylistener in java not working -

i want java program running in background default, use keylistener call changewallpaper class. changewallpaper class definently works, keylistener not call method. keyevent changed later it's testing.

import java.awt.event.keyevent; import java.awt.event.keylistener; public class listener implements keylistener { public static void main(string[] args){ } @override public void keyreleased(keyevent arg0) { int key = arg0.getkeycode(); if (key == keyevent.vk_up) { changewallpaper.main(); } } @override public void keytyped(keyevent arg0) { int key = arg0.getkeycode(); if (key == keyevent.vk_up) { changewallpaper.main(); } } @override public void keypressed(keyevent arg0) { int key = arg0.getkeycode(); if (key == keyevent.vk_up) { changewallpaper.main(); } } } 

a keylistener not listen keyboard events indiscriminately - listens events on particular component, when component has keyboard focus. have attach listener addkeylistener method or similar.

see java how write key listener tutorial