How to use

isSortable

method

in

org.jfree.ui.about.SystemPropertiesTableModel

/**
 * Sorts on the specified column.
 *
 * @param column  the column index.
 * @param ascending  a flag that controls the sort order.
 *
 */
public void sortByColumn(final int column, final boolean ascending) {
  if (isSortable(column)) {
    super.sortByColumn(column, ascending);
    Collections.sort(this.properties,
        new SystemPropertyComparator(ascending));
  }
}

/**
 * Sorts on the specified column.
 *
 * @param column  the column index.
 * @param ascending  a flag that controls the sort order.
 *
 */
public void sortByColumn(final int column, final boolean ascending) {
  if (isSortable(column)) {
    super.sortByColumn(column, ascending);
    Collections.sort(this.properties, new SystemPropertyComparator(ascending));
  }
}

/**
 * Sorts on the specified column.
 *
 * @param column  the column index.
 * @param ascending  a flag that controls the sort order.
 *
 */
public void sortByColumn(final int column, final boolean ascending) {
  if (isSortable(column)) {
    super.sortByColumn(column, ascending);
    Collections.sort(this.properties,
        new SystemPropertyComparator(ascending));
  }
}