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.TextField;
import javax.microedition.midlet.MIDlet;

public class ExampleMIDlet extends MIDlet implements CommandListener {
    private Command exitCommand;
    private Form mainForm;
 
    /**
     * Constructor. Constructs the object and initializes displayables.
     */
    public ExampleMIDlet() {
        mainForm = new Form("ExampleMIDlet");
 
        // Create a phone number field, which allows a call to be made
        mainForm.append(new TextField("Phone number", null, 20,
                TextField.PHONENUMBER));
 
        exitCommand = new Command("Exit", Command.EXIT, 0);
        mainForm.addCommand(exitCommand);
        mainForm.setCommandListener(this);
    }
 
    /**
     * Called when the MIDlet is started.
     */
    public void startApp() {
        Display.getDisplay(this).setCurrent(mainForm);
    }
 
    // Other inherited methods omitted for brevity
    // ...
 
    /**
     * From CommandListener.
     * Called by the system to indicate that a command has been invoked on a
     * particular displayable.
     * @param command the command that was invoked
     * @param displayable the displayable where the command was invoked
     */
    public void commandAction(Command command, Displayable displayable) {
        if (command == exitCommand) {
            // Exit the MIDlet
            destroyApp(true);
            notifyDestroyed();
        }
    }