JComboBoxのItemをキー入力やJPopupMenuでコピーする

JComboBox<String> combo1 = new JComboBox<>(makeModel(5));
Action copy = new AbstractAction() {
  @Override public void actionPerformed(ActionEvent e) {
    JComboBox<?> combo = (JComboBox<?>) e.getSource();
    Optional.ofNullable(combo.getSelectedItem()).ifPresent(text -> {
      Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
      Transferable contents = new StringSelection(Objects.toString(text));
      clipboard.setContents(contents, null);
      System.out.println(text);
    });
  }
};
ActionMap am = combo1.getActionMap();
am.put(COPY_KEY, copy);
int modifiers = InputEvent.CTRL_DOWN_MASK;
KeyStroke keyStroke = KeyStroke.getKeyStroke(KeyEvent.VK_C, modifiers);
InputMap im = combo1.getInputMap(JComponent.WHEN_FOCUSED);
im.put(keyStroke, COPY_KEY);

JPopupMenu popup = new JPopupMenu();
popup.add(COPY_KEY).addActionListener(e -> {
  Object o = popup.getInvoker();
  Container c = o instanceof JComboBox
    ? (Container) o
    : SwingUtilities.getAncestorOfClass(JComboBox.class, (Component) o);
  if (c instanceof JComboBox) {
    JComboBox<?> combo = (JComboBox<?>) c;
    Action a = combo.getActionMap().get(COPY_KEY);
    a.actionPerformed(new ActionEvent(combo, e.getID(), e.getActionCommand()));
    // KeyEvent keyEvent = new KeyEvent(combo, 0, 0, 0, 0, 'C');
    // SwingUtilities.notifyAction(a, keyStroke, keyEvent, combo, modifiers);
  }
});
combo1.setComponentPopupMenu(popup);