Java - Agregar Valor resistencia y Colorear Jtextfield de Texto

public class JavaSwing extends JFrame implements KeyListener{

	JTextField txtBox;

	public JavaSwing(){

		// Inizializacion

		super("Java Swing");

		setSize(300, 300);

		setDefaultCloseOperation(EXIT_ON_CLOSE);

		// Componentes

		txtBox = new JTextField(5);

		txtBox.addKeyListener(this);

		JPanel pnlNumeros = new JPanel();

		pnlNumeros.add(txtBox);

		// Contenedor

		Container contenedor = getContentPane();

		contenedor.add(pnlNumeros, BorderLayout.NORTH);

	}

	public static void main(String[] args) {

		JavaSwing ventana = new JavaSwing();

		ventana.setVisible(true);

	}

	public void keyTyped(KeyEvent e) {}

	public void keyPressed(KeyEvent e) {}

	public void keyReleased(KeyEvent e) {

		if (e.getKeyCode() == 10){

			txtBox.setBackground(Color.red);

		}

	}

}