Como escrever em Applets?

import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JApplet;
import javax.swing.JLabel;

/**
 *
 * @author Ton
 */
public class NewJApplet2 extends JApplet {

    private JLabel lblPts1;
    private JLabel lblArestas;
    private JLabel lblDois1;
    private JLabel lblMais1;
    private JLabel lblPts2;
    private JLabel lblInternos;
    private JLabel lblIgual1;
    private JLabel lblArestas2;
    private JLabel lblDois2;
    private JLabel lblMais2;
    private JLabel lblInternos2;
    private JLabel lblIgual2;
    private JLabel lblArea;

    @Override
    public void init() {
        lblPts1 = new JLabel("Pontos nas");
        lblArestas = new JLabel("Arestas");
        lblDois1 = new JLabel("2");
        lblMais1 = new JLabel("+");
        lblPts2 = new JLabel("Pontos no");
        lblInternos = new JLabel("Interior");
        lblIgual1 = new JLabel("=");
        lblArestas2 = new JLabel("50");
        lblDois2 = new JLabel("2");
        lblMais2 = new JLabel("+");
        lblInternos2 = new JLabel("100");
        lblIgual2 = new JLabel("=");
        lblArea = new JLabel("125");


        Container c=getContentPane();
        GridBagConstraints cons = new GridBagConstraints();
        GridBagLayout layout = new GridBagLayout();
        c.setLayout(layout);

        cons.fill = GridBagConstraints.BOTH;
        cons.gridx = 0;
        cons.gridy = 0;
        c.add(lblPts1, cons);

        cons.gridx = 0;
        cons.gridy = 1;
        c.add(lblArestas, cons);

        cons.gridx = 0;
        cons.gridy = 2;
        c.add(lblDois1, cons);

        cons.gridx = 1;
        cons.gridy = 0;
        cons.gridheight = 3;
        c.add(lblMais1, cons);

        cons.gridx = 2;
        cons.gridy = 0;
        cons.gridheight = 1;
        c.add(lblPts2, cons);

        cons.gridx = 2;
        cons.gridy = 1;
        c.add(lblInternos, cons);

        cons.gridx = 3;
        cons.gridy = 0;
        cons.gridheight = 3;
        c.add(lblIgual1, cons);

        cons.gridx = 4;
        cons.gridy = 1;
        cons.gridheight = 1;
        c.add(lblArestas2, cons);

        cons.gridx = 4;
        cons.gridy = 2;
        c.add(lblDois2, cons);

        cons.gridx = 5;
        cons.gridy = 0;
        cons.gridheight = 3;
        c.add(lblMais2, cons);

        cons.gridx = 6;
        cons.gridy = 0;
        c.add(lblInternos2, cons);

        cons.gridx = 7;
        cons.gridy = 0;
        c.add(lblIgual2, cons);

        cons.gridx = 8;
        cons.gridy = 0;
        c.add(lblArea, cons);
    }
}