Erro com Event ao tentar criar itens no JFrame

public void actionPerformed(ActionEvent e) {
        JPanel painel = new JPanel();
        JComboBox comboBox = new JComboBox();
        JTextField campoDeTexto = new JTextField();
        JButton ce = new JButton();

        if (e.getSource() == jButton1) {
            String item = jComboBox1.getSelectedItem().toString();
            if(item.equals("Cadastrar Disciplina")) {
                    System.out.println("Cadastro Disciplina");
                    painel.setBorder(javax.swing.BorderFactory.createTitledBorder(null, "Cadastro de Disciplina", javax.swing.border.TitledBorder.DEFAULT_JUSTIFICATION, javax.swing.border.TitledBorder.DEFAULT_POSITION, new java.awt.Font("Tahoma", 1, 11), new java.awt.Color(0, 153, 204))); // NOI18N
                    ce.setText("Cadastrar");

                    javax.swing.GroupLayout painelLayout = new javax.swing.GroupLayout(painel);
                    painel.setLayout(painelLayout);
                    painelLayout.setHorizontalGroup(
                        painelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addGroup(painelLayout.createSequentialGroup()
                            .addContainerGap()
                             .addGroup(painelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                        .addComponent(campoDeTexto, javax.swing.GroupLayout.PREFERRED_SIZE, 193, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addComponent(ce, javax.swing.GroupLayout.PREFERRED_SIZE, 86, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addContainerGap(152, Short.MAX_VALUE))
                );
                    painelLayout.setVerticalGroup(
                    painelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                        .addGroup(painelLayout.createSequentialGroup()
                        .addContainerGap()
                        .addComponent(campoDeTexto, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(18, 18, 18)
                        .addComponent(ce)
                        .addContainerGap(28, Short.MAX_VALUE))
                );
            }
            else if(item.equals("Cadastrar Tópico")) {

            }
            else if(item.equals("Cadastrar Item")) {

            }
            else if(item.equals("Cadastrar SubItem")) {

            }
            else if(item.equals("Cadastrar Detalhe")) {

            }
            else if(item.equals("Cadastrar Questão")) {

            }
            else if(item.equals("Editar Disciplina")) {

            }
            else if(item.equals("Editar Tópico")) {

            }
            else if(item.equals("Editar Item")) {

            }
            else if(item.equals("Editar SubItem")) {

            }
            else if(item.equals("Editar Detalhe")) {

            }
            else if(item.equals("Cadastrar Questão")) {

            }

            layout.setVerticalGroup(
                layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addComponent(painel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 18, Short.MAX_VALUE))
            );
        }
    }