RadioButton

 private void jBttnCadastrarActionPerformed(java.awt.event.ActionEvent evt) {                                               
        // TODO add your handling code here:
        Cliente c = new Cliente();
        c.setNome(clienteNome.getText());
        c.setSexo(RadioButtonMasculino.getText());
        c.setSexo(RadioButtonFeminino.getText());
        c.setRg(clienteRg.getText());
        c.setCpf(clienteCpf.getText());
        c.setEndereco(clienteEndereco.getText());

        if (clienteNome.getText().equals("")) {
            JOptionPane.showMessageDialog(null, "Nome em branco.");
            clienteNome.requestFocus();
            return;
        } else {
            if (clienteRg.getText().equals("") ) {
                JOptionPane.showMessageDialog(null, "Rg em branco!");
                clienteRg.requestFocus();
                return;
            } else {
                if (clienteCpf.getText().equals("")) {
                    JOptionPane.showMessageDialog(null, "Cpf em branco!");
                    clienteCpf.requestFocus();
                    return;
                } else {
                    if (clienteEndereco.getText().equals("")) {
                        JOptionPane.showMessageDialog(null, "Endereço em branco!");
                        clienteEndereco.requestFocus();
                        return;
                    }
                    if (RadioButtonMasculino.isSelected()){      
                        RadioButtonMasculino.requestFocus();
                    }
                    if (RadioButtonFeminino.isSelected()){
                        RadioButtonFeminino.requestFocus();
                    }
                }

            }

            




            try {

                fachada.salvar(c);
                clienteNome.setText("");
                RadioButtonMasculino.setText("masculino");
                RadioButtonFeminino.setText("feminino");
                clienteRg.setText("");
                clienteCpf.setText("");
                clienteEndereco.setText("");

                JOptionPane.showMessageDialog(null, "Cliente cadastrado com sucesso!");
                clienteNome.requestFocus();
            } catch (GeralException ex) {
                JOptionPane.showMessageDialog(null, ex.getMessage());
            }
        }
    }                                              

        private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
            // TODO add your handling code here:
            dispose();
    }                                        

    private void RadioButtonMasculinoActionPerformed(java.awt.event.ActionEvent evt) {
           
        // TODO add your handling code here:
    }

    private void RadioButtonFemininoActionPerformed(java.awt.event.ActionEvent evt) {
         
        // TODO add your handling code here:
    }

    private void clienteEnderecoActionPerformed(java.awt.event.ActionEvent evt) {
        // TODO add your handling code here:
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /*
         * Set the Nimbus look and feel
         */
        //<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(JFCadastroCliente.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(JFCadastroCliente.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(JFCadastroCliente.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(JFCadastroCliente.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /*
         * Create and display the form
         */
        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {
                new JFCadastroCliente().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify
    private javax.swing.JRadioButton RadioButtonFeminino;
    private javax.swing.JRadioButton RadioButtonMasculino;
    private javax.swing.ButtonGroup buttonGroup1;
    private javax.swing.ButtonGroup buttonGroup2;
    private javax.swing.ButtonGroup buttonGroup3;
    private javax.swing.ButtonGroup buttonGroup4;
    private javax.swing.ButtonGroup buttonGroup5;
    private javax.swing.JFormattedTextField clienteCpf;
    private javax.swing.JTextField clienteEndereco;
    private javax.swing.JTextField clienteNome;
    private javax.swing.JFormattedTextField clienteRg;
    private javax.swing.JButton jBttnCadastrar;
    private javax.swing.JButton jButton1;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JLabel jLabel5;
    private javax.swing.JLabel jLabel6;
    // End of variables declaration
}

Bom turma tou com essa duvida aqui ver so quero colocar a opção para sexo no radiobutton mais nao tou conserguindo de nenhuma forma tb pq nao sei como implementar
peço que vcs olhe esse codico e vejam onde eu tou errando pf obg.

Você instanciou o JRadioButton :?:

:thumbup:

Isso, voce o instanciou, falta adiciona-lo ao contentPane