JTableのヘッダやセル罫線の色を統一して罫線の幅が変化しないよう設定する

JTable table = new JTable(10, 3) {
  private final CellBorder border = new CellBorder(2, 2, 1, 2);
  @Override public Component prepareEditor(
      TableCellEditor editor, int row, int column) {
    Component c = super.prepareEditor(editor, row, column);
    if (c instanceof JTextField) {
      ((JComponent) c).setBorder(border);
      border.setStartCell(column == 0);
    }
    return c;
  }
};
table.setAutoCreateRowSorter(true);
table.setFillsViewportHeight(true);
table.setShowVerticalLines(false);
table.setGridColor(Color.ORANGE);
table.setSelectionForeground(Color.BLACK);
table.setSelectionBackground(new Color(0x64_AA_EE_FF, true));
table.setIntercellSpacing(new Dimension(0, 1));
table.setBorder(BorderFactory.createEmptyBorder());
table.setDefaultRenderer(Object.class, new DefaultTableCellRenderer() {
  private final CellBorder border = new CellBorder(2, 2, 1, 2);
  @Override public Component getTableCellRendererComponent(
        JTable table, Object value, boolean isSelected, boolean hasFocus,
        int row, int column) {
    JLabel c = (JLabel) super.getTableCellRendererComponent(
        table, value, isSelected, hasFocus, row, column);
    border.setStartCell(column == 0);
    c.setBorder(border);
    return c;
  }
});

JTableHeader header = table.getTableHeader();
header.setBorder(BorderFactory.createEmptyBorder());
header.setDefaultRenderer(new DefaultTableCellRenderer() {
  private final CellBorder border = new CellBorder(2, 2, 1, 2);
  @Override public Component getTableCellRendererComponent(
        JTable table, Object value, boolean isSelected, boolean hasFocus,
        int row, int column) {
    JLabel c = (JLabel) super.getTableCellRendererComponent(
        table, value, isSelected, hasFocus, row, column);
    border.setStartCell(column == 0);
    c.setHorizontalAlignment(SwingConstants.CENTER);
    c.setBorder(border);
    c.setBackground(table.getGridColor());
    return c;
  }
});