how to create class alert using lcdui package in blackberry

Question

Advance Thanks.i am new to blackberry developement.i try the following code for creating alert using lcdui package.but nothing will coming when i am running

Plz help me.

package alertpack;

import javax.microedition.lcdui.Alert; import javax.microedition.lcdui.AlertType; import javax.microedition.lcdui.Command; import javax.microedition.lcdui.CommandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.Form; import javax.microedition.lcdui.Screen; import javax.microedition.midlet.MIDlet; import javax.microedition.midlet.MIDletStateChangeException;

import net.rim.device.api.ui.Color; import net.rim.device.api.ui.Graphics;

public class alertclass extends MIDlet implements CommandListener {

private Display display;

private Alert alert;

private Form form = new Form("Throw Exception");

private Command exit = new Command("Exit", Command.SCREEN, 1);

private boolean exitFlag = false;

public alertclass(){ display = Display.getDisplay(this); form.addCommand(exit); form.setCommandListener(this); }

protected void destroyApp(boolean unconditional) throws MIDletStateChangeException { // TODO Auto-generated method stub if (unconditional == false) { throw new MIDletStateChangeException(); }

}

protected void pauseApp() { // TODO Auto-generated method stub

}

protected void startApp() throws MIDletStateChangeException { // TODO Auto-generated method stub display.setCurrent(form);

}

public void commandAction(Command c, Displayable d) { // TODO Auto-generated method stub

if (c == exit) { try { if (exitFlag == false) { alert = new Alert("Busy", "Please try again.", null, AlertType.WARNING); alert.setTimeout(Alert.FOREVER); display.setCurrent(alert, form); destroyApp(false); } else { destroyApp(true); notifyDestroyed(); } } catch (Exception exception) { exitFlag = true; } }

}

}