Java GUI - Convertidor de temperatura

public class convertidorGUI extends javax.swing.JFrame {
    public convertidorGUI() {
        initComponents();
    }
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">//GEN-BEGIN:initComponents
    private void initComponents() {

        tempVar = new javax.swing.JTextField();
        celciusLabel = new javax.swing.JLabel();
        convertTemp = new javax.swing.JButton();
        farLabel = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setTitle("Convertidor");

        tempVar.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                tempVarActionPerformed(evt);
            }
        });

        celciusLabel.setText("Celcius");

        convertTemp.setText("Convertir");
        convertTemp.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                convertTempActionPerformed(evt);
            }
        });

        farLabel.setText("Fahrenheit");

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(convertTemp)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(farLabel))
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(tempVar, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(celciusLabel)))
                .addContainerGap(40, Short.MAX_VALUE))
        );

        layout.linkSize(javax.swing.SwingConstants.HORIZONTAL, new java.awt.Component[] {convertTemp, tempVar});

        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(tempVar, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(celciusLabel))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(convertTemp)
                    .addComponent(farLabel))
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>//GEN-END:initComponents

private void convertTempActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_convertTempActionPerformed
//Parse degrees Celsius as a double and convert to Fahrenheit.
    int tempFahr = (int)((Double.parseDouble(tempVar.getText()))
            * 1.8 + 32);
    farLabel.setText(tempFahr + " Fahrenheit");
}//GEN-LAST:event_convertTempActionPerformed

private void tempVarActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_tempVarActionPerformed
 // TODO add your handling code here:
}//GEN-LAST:event_tempVarActionPerformed

    public static void main(String args[]) {
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /*
         * If Nimbus (introduced in Java SE 6) is not available, stay with the
         * default look and feel. For details see
         * http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(convertidorGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(convertidorGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(convertidorGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(convertidorGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new convertidorGUI().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify//GEN-BEGIN:variables
    private javax.swing.JLabel celciusLabel;
    private javax.swing.JButton convertTemp;
    private javax.swing.JLabel farLabel;
    private javax.swing.JTextField tempVar;
    // End of variables declaration//GEN-END:variables
}