import javax.microedition.lcdui.*;import javax.microedition.midlet.*;public class HelloMIDlet extends MIDlet implements CommandListener{        private Display display;        private HelloCanvas myCanvas;        private Command   CMD_EXIT = new Command("退出", Command.SCREEN, 1);        public HelloMIDlet()        {               	myCanvas = new HelloCanvas();                display = Display.getDisplay(this);                myCanvas.addCommand(CMD_EXIT);                                                myCanvas.setCommandListener(this);        }        public void startApp()        {                                 display.setCurrent(myCanvas);        }        public void pauseApp()        {        }        public void destroyApp(boolean unconditional)        {        }        public void commandAction(Command cmd, Displayable disp) {        if(cmd == CMD_EXIT){        destroyApp(false);        notifyDestroyed();        }                       }}