Please have a look at the following code
/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
/**
 */
public class Midlet extends MIDlet{
    private Form f;
    private Display d;
    private Command start,stop;
    private Thread t;
    public Midlet()
    {
        t = new Thread(new TurnLightOn());
    }
    public void startApp() 
    {
        f = new Form("Back Light On");
       d = Display.getDisplay(this);
       d.setCurrent(f);        
       start = new Command("Turn On",Command.OK,0);
       stop = new Command("Turn Off",Command.OK,1);
       f.addCommand(start);
       f.setCommandListener(new Action());
    }
    public void pauseApp() {
    }
    public void destroyApp(boolean unconditional)
    {
        this.notifyDestroyed();
    }
    private class Action implements CommandListener
    {
        public void commandAction(Command c, Displayable dis) 
        {
            f.append("Light is Turnning On");
            t.start();
        }
    }
     private class ActionOff implements CommandListener
    {
        public void commandAction(Command c, Displayable dis) 
        {
        }
    }
    private class TurnLightOn implements Runnable
    {
        public void run() 
        {
            f.append("Working");
            for(int i=0;i<100;i++)
            {
                try 
                {
                    d.flashBacklight(200);
                    d.vibrate(200);
                    Thread.sleep(1000);
                } 
                catch (InterruptedException ex)
                {
                    ex.printStackTrace();
                }
            }
        }
    }
}
First, Please note I am a 100% newbie to Java Mobile.
In here, I am making the light on and vibrate on when user click the button. However, I really wanted to create a SOS application which turn the whole screen into white, and go to black, like that, in the thread. I guess I didn't achieve that by this app because even the lights are on, the buttons are still there. I tried to turn the "Form" color to "white" but it seems like JME has no "Color" class! Please help!