重构后引用ActionMap的NullPointerException

Question

添加ViewButtons类时，在尝试引用NullPointerException时会引发actionMap。删除ViewButtons类并取消注释下面的代码可以解决问题。但是，我正在尝试分离我的代码，因为应用程序将扩展。如何在不生成actionMap的情况下引用ViewButtons中的NullPointerException？

public class View extends FrameView {

private javax.swing.JButton saveButton;
private javax.swing.JPanel mainPanel;
private javax.swing.JPanel tableContainer

    public View(SingleFrameApplication app) {
        super(app);
        initComponents();
     }

    private void initComponents() {

        mainPanel = new javax.swing.JPanel();
        tableContainer = new JPanel();
        saveButton = new javax.swing.JButton();

        javax.swing.ActionMap actionMap = org.jdesktop.application.Application.getInstance(MyApp.class).getContext().getActionMap(View.class, this);

        ViewButtons viewButtons = new ViewButtons(actionMap);

        mainPanel.setName("mainPanel"); // NOI18N
        mainPanel.setLayout(new BorderLayout());

        tableContainer.setName("tableContainer");
        tableContainer.setLayout(new BorderLayout());

        //        buttonPanel = new JPanel();
        //        buttonPanel.setMinimumSize(new Dimension(800, 30));
        //        buttonPanel.setName("buttonPanel");

        //        saveButton.setAction(actionMap.get("save")); // NOI18N
        //        saveButton.setName("saveButton"); // NOI18N
        //        buttonPanel.add(saveButton);

        //        tableContainer.add(buttonPanel, BorderLayout.PAGE_END);
        tableContainer.add(viewButtons.getMainComponent(), BorderLayout.PAGE_END);

        setComponent(mainPanel);
    }

    class ViewButtons {

        private JPanel buttonPanel = new JPanel();

        public ViewButtons(ActionMap actionMap) {
            buttonPanel.setMinimumSize(new Dimension(800, 30));
            buttonPanel.setName("buttonPanel");

            saveButton.setAction(actionMap.get("save")); <<<<- NULLPONTER EXCEPTION
            saveButton.setName("saveButton"); // NOI18N
            buttonPanel.add(saveButton);
        }

        public JComponent getMainComponent() {
            return buttonPanel;
        }
    }