dúvida básica em J2ME

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package hello;

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import org.netbeans.microedition.lcdui.SplashScreen;

/**
 * @author Petrus Bastos
 */
public class HelloMIDlet extends MIDlet implements CommandListener {

    private boolean midletPaused = false;

    //<editor-fold defaultstate="collapsed" desc=" Generated Fields ">
    private Command exitCommand;
    private Command itemCommand;
    private Command exitCommand1;
    private SplashScreen splashScreen;
    private List list;
    private Alert alert;
    private Image image1;
    private Font font1;
    //</editor-fold>

    /**
     * The HelloMIDlet constructor.
     */
    public HelloMIDlet() {
    }

    //<editor-fold defaultstate="collapsed" desc=" Generated Methods ">
    //</editor-fold>

    //<editor-fold defaultstate="collapsed" desc=" Generated Method: initialize ">
    /**
     * Initilizes the application.
     * It is called only once when the MIDlet is started. The method is called before the <code>startMIDlet</code> method.
     */
    private void initialize() {
        // write pre-initialize user code here
 
        // write post-initialize user code here
    }
    //</editor-fold>

    //<editor-fold defaultstate="collapsed" desc=" Generated Method: startMIDlet ">
    /**
     * Performs an action assigned to the Mobile Device - MIDlet Started point.
     */
    public void startMIDlet() {
        // write pre-action user code here
        switchDisplayable(null, getSplashScreen());
    // write post-action user code here
    }
    //</editor-fold>

    //<editor-fold defaultstate="collapsed" desc=" Generated Method: resumeMIDlet ">
    /**
     * Performs an action assigned to the Mobile Device - MIDlet Resumed point.
     */
    public void resumeMIDlet() {
        // write pre-action user code here
       
 
        // write post-action user code here
    }
    //</editor-fold>

    //<editor-fold defaultstate="collapsed" desc=" Generated Method: switchDisplayable ">
    /**
     * Switches a current displayable in a display. The <code>display</code> instance is taken from <code>getDisplay</code> method. This method is used by all actions in the design for switching displayable.
     * @param alert the Alert which is temporarily set to the display; if <code>null</code>, then <code>nextDisplayable</code> is set immediately
     * @param nextDisplayable the Displayable to be set
     */
    public void switchDisplayable(Alert alert, Displayable nextDisplayable) {
        // write pre-switch user code here
        Display display = getDisplay();
        if (alert == null) {
            display.setCurrent(nextDisplayable);
        } else {
            display.setCurrent(alert, nextDisplayable);
        }
    // write post-switch user code here
    }
    //</editor-fold>

    //<editor-fold defaultstate="collapsed" desc=" Generated Method: commandAction for Displayables ">
    /**
     * Called by a system to indicated 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) {
        // write pre-action user code here
        if (displayable == list) {
            if (command == List.SELECT_COMMAND) {
                // write pre-action user code here                   
                listAction();
            // write post-action user code here
            } else if (command == exitCommand1) {
                // write pre-action user code here
                exitMIDlet();
            // write post-action user code here
            } else if (command == itemCommand) {
                // write pre-action user code here
                switchDisplayable(getAlert(), getList());
            // write post-action user code here
            }
        } else if (displayable == splashScreen) {
            if (command == SplashScreen.DISMISS_COMMAND) {
                // write pre-action user code here
                switchDisplayable(null, getList());
            // write post-action user code here
            }
        }
    // write post-action user code here
    }
    //</editor-fold>


    //<editor-fold defaultstate="collapsed" desc=" Generated Getter: exitCommand ">
    /**
     * Returns an initiliazed instance of exitCommand component.
     * @return the initialized component instance
     */
    public Command getExitCommand() {
        if (exitCommand == null) {
            // write pre-init user code here
            exitCommand = new Command("Exit", Command.EXIT, 0);
        // write post-init user code here
        }
        return exitCommand;
    }
    //</editor-fold>

    //<editor-fold defaultstate="collapsed" desc=" Generated Getter: splashScreen ">
    /**
     * Returns an initiliazed instance of splashScreen component.
     * @return the initialized component instance
     */
    public SplashScreen getSplashScreen() {
        if (splashScreen == null) {
            // write pre-init user code here
            splashScreen = new SplashScreen(getDisplay());
            splashScreen.setTitle("splashScreen");
            splashScreen.setCommandListener(this);
            splashScreen.setFullScreenMode(true);
            splashScreen.setImage(getImage1());
            splashScreen.setText("Aguarde...");
            splashScreen.setTextFont(getFont1());
            splashScreen.setTimeout(2000);
        // write post-init user code here
        }
        return splashScreen;
    }
    //</editor-fold>

    //<editor-fold defaultstate="collapsed" desc=" Generated Getter: image1 ">
    /**
     * Returns an initiliazed instance of image1 component.
     * @return the initialized component instance
     */
    public Image getImage1() {
        if (image1 == null) {
            // write pre-init user code here
            try {
                image1 = Image.createImage("/logo.gif");
            } catch (java.io.IOException e) {
                e.printStackTrace();
            }
        // write post-init user code here
        }
        return image1;
    }
    //</editor-fold>

    //<editor-fold defaultstate="collapsed" desc=" Generated Getter: itemCommand ">
    /**
     * Returns an initiliazed instance of itemCommand component.
     * @return the initialized component instance
     */
    public Command getItemCommand() {
        if (itemCommand == null) {
            // write pre-init user code here
            itemCommand = new Command("Escolher", Command.SCREEN, 0);
        // write post-init user code here
        }
        return itemCommand;
    }
    //</editor-fold>



    //<editor-fold defaultstate="collapsed" desc=" Generated Method: listAction ">
    /**
     * Performs an action assigned to the selected list element in the list component.
     */
    public void listAction() {
        // enter pre-action user code here
        switch (getList().getSelectedIndex()) {
            case 0:
                // write pre-action user code here              
 
                // write post-action user code here
                break;
            case 1:
                // write pre-action user code here
 
                // write post-action user code here
                break;
            case 2:
                // write pre-action user code here
 
                // write post-action user code here
                break;
            case 3:
                // write pre-action user code here
 
                // write post-action user code here
                break;
        }
    // enter post-action user code here
    }
    //</editor-fold>

    //<editor-fold defaultstate="collapsed" desc=" Generated Getter: font1 ">
    /**
     * Returns an initiliazed instance of font1 component.
     * @return the initialized component instance
     */
    public Font getFont1() {
        if (font1 == null) {
            // write pre-init user code here
            font1 = Font.getFont(Font.FACE_SYSTEM, Font.STYLE_PLAIN, Font.SIZE_SMALL);
        // write post-init user code here
        }
        return font1;
    }
    //</editor-fold>

    //<editor-fold defaultstate="collapsed" desc=" Generated Getter: exitCommand1 ">
    /**
     * Returns an initiliazed instance of exitCommand1 component.
     * @return the initialized component instance
     */
    public Command getExitCommand1() {
        if (exitCommand1 == null) {
            // write pre-init user code here
            exitCommand1 = new Command("Sair", Command.EXIT, 0);
        // write post-init user code here
        }
        return exitCommand1;
    }
    //</editor-fold>

    //<editor-fold defaultstate="collapsed" desc=" Generated Getter: alert ">
    /**
     * Returns an initiliazed instance of alert component.
     * @return the initialized component instance
     */
    public Alert getAlert() {
        if (alert == null) {
            // write pre-init user code here
            alert = new Alert("Alerta", "Você escolheu: " + (list.getSelectedIndex() + 1), null, AlertType.INFO);
            alert.setTimeout(Alert.FOREVER);
        // write post-init user code here
        }
        return alert;
    }
    //</editor-fold>

    //<editor-fold defaultstate="collapsed" desc=" Generated Getter: list ">
    /**
     * Returns an initiliazed instance of list component.
     * @return the initialized component instance
     */
    public List getList() {
        if (list == null) {
            // write pre-init user code here
            list = new List("Lista de Cobran\u00E7as", Choice.EXCLUSIVE);
            list.append("Cobran\u00E7a 1", null);
            list.append("Cobran\u00E7a 2", null);
            list.append("Cobran\u00E7a 3", null);
            list.append("Cobran\u00E7a 4", null);
            list.addCommand(getItemCommand());
            list.addCommand(getExitCommand1());
            list.setCommandListener(this);
            list.setFitPolicy(Choice.TEXT_WRAP_DEFAULT);
            list.setSelectCommand(getItemCommand());
            list.setSelectedFlags(new boolean[] { false, false, false, false });
        // write post-init user code here
        }
        return list;
    }
    //</editor-fold>

    /**
     * Returns a display instance.
     * @return the display instance.
     */
    public Display getDisplay() {
        return Display.getDisplay(this);
    }

    /**
     * Exits MIDlet.
     */
    public void exitMIDlet() {
        switchDisplayable(null, null);
        destroyApp(true);
        notifyDestroyed();
    }

    /**
     * Called when MIDlet is started.
     * Checks whether the MIDlet have been already started and initialize/starts or resumes the MIDlet.
     */
    public void startApp() {
        if (midletPaused) {
            resumeMIDlet();
        } else {
            initialize();
            startMIDlet();
        }
        midletPaused = false;
    }

    /**
     * Called when MIDlet is paused.
     */
    public void pauseApp() {
        midletPaused = true;
    }

    /**
     * Called to signal the MIDlet to terminate.
     * @param unconditional if true, then the MIDlet has to be unconditionally terminated and all resources has to be released.
     */
    public void destroyApp(boolean unconditional) {
    }
}