JOptionPaneで使用するメッセージダイアログのOKボタンテキストを変更する

UIManager.put("OptionPane.okButtonText", "back");

JLabel label2 = new JLabel("JButton#setFocusPainted(false)");
label2.addHierarchyListener(e -> {
  Component c = e.getComponent();
  if ((e.getChangeFlags() & HierarchyEvent.SHOWING_CHANGED) != 0 &&
        c.isShowing()) {
    descendants(((JComponent) c).getRootPane())
        .filter(JButton.class::isInstance)
        .map(JButton.class::cast)
        .findFirst()
        .ifPresent(b -> {
          b.setFocusPainted(false);
          b.setText("back2");
        });
  }
});
JButton button2 = new JButton("HierarchyListener + setFocusPainted(false)");
button2.addActionListener(e -> {
  Component p = ((JComponent) e.getSource()).getRootPane();
  JOptionPane.showMessageDialog(
      p, label2, "title2", JOptionPane.PLAIN_MESSAGE);
});

// https://docs.oracle.com/javase/tutorial/uiswing/components/dialog.html#button
JButton button3 = new JButton("showOptionDialog");
button3.addActionListener(e -> {
  Object[] options = {"Yes, please"}; // {"Yes, please", "No way!"};
  JOptionPane.showOptionDialog(
      ((JComponent) e.getSource()).getRootPane(),
      "Would you like green eggs and ham?",
      "A Silly Question",
      JOptionPane.OK_OPTION,
      JOptionPane.PLAIN_MESSAGE,
      null,
      options,
      options[0]);
});