Qual o problema com esse código?

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import java.util.*;
import java.io.*;

class DateFieldTeste extends MIDlet implements CommandListener {
	Form form;
	DateField campoData, mostraData;
	Command cmOK, cmSair;
	Display dsTela;
	
	public DateFieldTeste() {
		
		dsTela = Display.getDisplay(this);
		
		campoData = new DateField("Digite uma data", DateField.DATE);
		mostraData = new DateField("Data digitada", DateField.DATE);
		
		cmOK = new Command("OK", Command.OK, 1);
		cmSair = new Command("Sair", Command.EXIT, 1);
		
		form = new Form("Teste DateField");
		form.append(campoData);
		form.append(mostraData);
		form.addCommand(cmOK);
		form.addCommand(cmSair);
		form.setCommandListener(this);
	}
	
	public void commandAction(Command c, Displayable s) {
		if (c == cmOK) {
			mostraData.setDate(campoData.getDate());
		}
		
		if (c == cmSair) {
			destroyApp(true);
		}
	}
	
	// ------------------------MIDLET------------------------------------
		public void destroyApp(boolean unconditional){
			notifyDestroyed();
		}

		public void startApp(){
			dsTela.setCurrent(form);
		}

		public void pauseApp(){}
}