device configuration in j2me

import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.TextField;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;

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

public class LoginScreen extends MIDlet{
private Display display;
private Command cExit;

public void startApp(){
display = Display.getDisplay(this);

cExit = new Command("Quit", Command.EXIT, 0);

Canvas canvas = new DummyCanvas();

Runtime runtime = Runtime.getRuntime();
Form form = new Form("Attributes");

form.append(new StringItem("Know Your Mobile", ""));
form.append(new StringItem("Total Memory:", String.valueOf(runtime.totalMemory()/1024)+"Kb"));
form.append(new StringItem("Free Memory:", String.valueOf(runtime.freeMemory()/1024)+"Kb"));
form.append(new StringItem("n", null));
form.append(System.getProperty("microedition.configuration"));
form.append(System.getProperty("microedition.profiles"));

boolean isColor = display.isColor();

form.append(new StringItem(isColor ? "Colors:": "Grays:", String.valueOf(display.numColors())));
form.append(new StringItem("Width: ", String.valueOf(canvas.getWidth())));
form.append(new StringItem("Height:", String.valueOf(canvas.getHeight())));
form.append(new StringItem("Repeat:", String.valueOf(canvas.hasRepeatEvents())));
form.append(new StringItem("Double Buff:", String.valueOf(canvas.isDoubleBuffered())));

form.addCommand(cExit);
form.setCommandListener(
new CommandListener(){
public void commandAction(Command c, Displayable d){
if (c == cExit){
destroyApp(false);
notifyDestroyed();
}
}
}
);

display.setCurrent(form);
}
public void pauseApp(){
}
public void destroyApp(boolean unconditional){
}
}

class DummyCanvas extends Canvas{
public void paint(Graphics g){
;
}
}