Imagens Aleatórias com J2ME-Novato ao extremo

private final short intervalMin = 0;
private final short intervalMax = 3;        

Random r = new Random();                          

short nr =(short) ( (r.nextInt() >>> 1) % (intervalMax + 1 - intervalMin) + intervalMin );

[size=9]import java.io.IOException;
import java.util.Random;

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;


public class TesteMIDlet extends MIDlet implements CommandListener
{
	private Display display;
	private TextBox txt1; 
	private TextBox txt2; 

	private Command cmExit;
		
	public TesteMIDlet ()
	{
		display = Display.getDisplay(this);
		cmExit = new Command("sair",Command.EXIT,1);
		txt1 = new TextBox("Bem vindo","Alo Mundo - Java!", 20, TextField.ANY);
		txt2 = new TextBox("Welcome","Hello World - Java!", 20, TextField.ANY);
		
		txt1.addCommand(cmExit);	
		txt1.setCommandListener(this);
		txt2.addCommand(cmExit);	
		txt2.setCommandListener(this);		
	}
	
	public void startApp()
		
	{
		String nome_img = "/imagem1.png";
		Image img = null;
		String nome_img2 = "/imagem2.png";
		Image img2 = null;
		try {
			img1 = Image.createImage(nome_img);
			img2 = Image.createImage(nome_img2);
		}catch (IOException e) {
			e.printStackTrace();
		}
		final short intervalMin = 1; 
		final short intervalMax = 2;        

		Random r = new Random();
		short number=(short) ( (r.nextInt() >>> 1) % (intervalMax + 1 - intervalMin) + intervalMin );    
	        if ( number  == 1 ) {
	    		Alert alert1 = new Alert ("teste1","",img1,AlertType.INFO);
	    		alert1.setTimeout(2000);
	        	display.setCurrent(alert1,txt1);//teste1        	
	        }
	        if ( number  == 2 ) {
	    		Alert alert2 = new Alert ("teste2","",img2,AlertType.INFO);
	    		alert2.setTimeout(2000);
	        	display.setCurrent(alert2,txt2);
	        }//teste2 	
	        }

	public void pauseApp() 
	{};

	public void destroyApp(boolean inconditional) 
	{};
	
	public void commandAction ( Command c, Displayable s)
	
	{
		if (c==cmExit)
		{
			destroyApp(false);
			notifyDestroyed();
		}	
	}			
}[/size]