Package En Java

package fundamentales;

/**
*
* @author Juan Marcos
*/
public class Frame_fundamentales extends javax.swing.JFrame {

/** Creates new form Frame_fundamentales */
publicFrame_fundamentales() {
initComponents();
}

/** This method is called from within the constructor to
* initialize the form.
* WARNING: Do NOT modify this code. The content ofthis method is
* always regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">private void initComponents() {

buttonGroup1 = new javax.swing.ButtonGroup();
jLabel1 = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();jTextField1 = new javax.swing.JTextField();
jTextField2 = new javax.swing.JTextField();
jLabel3 = new javax.swing.JLabel();
jLabel4 = new javax.swing.JLabel();jLabel5 = new javax.swing.JLabel();
jLabel6 = new javax.swing.JLabel();
jTextField3 = new javax.swing.JTextField();
jTextField4 = new javax.swing.JTextField();jTextField5 = new javax.swing.JTextField();
jTextField6 = new javax.swing.JTextField();
calcular = new javax.swing.JButton();
limpiar = new javax.swing.JButton();
jLabel7 =new javax.swing.JLabel();

setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setTitle("Operaciones Fundamentales Creado por Marcos Miranda");jLabel1.setText("1er numero");
jLabel2.setText("2do numero");
jLabel3.setText("Suma");
jLabel4.setText("Resta");
jLabel5.setText("Multiplicacion");jLabel6.setText("Divicion");

calcular.setText("CALCULAR");
calcular.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent...