JSplitPaneに設定した子コンポーネントの位置を入れ替える

JSplitPane split = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, left, right);
split.setResizeWeight(.4);

JButton button = new JButton("swap");
button.setFocusable(false);
button.addActionListener(e -> {
  Component left = split.getLeftComponent();
  Component right = split.getRightComponent();

  // split.removeAll(); // Divider is also removed
  split.remove(left);
  split.remove(right);
  // or:
  // split.setLeftComponent(null);
  // split.setRightComponent(null);

  split.setLeftComponent(right);
  split.setRightComponent(left);

  split.setResizeWeight(1d - split.getResizeWeight());
  if (check.isSelected()) {
    split.setDividerLocation(split.getDividerLocation());
  }
});