Why does my JTable sort an integer column incorrectly?

Question

I have a JTable that uses a DefaultTableModel and I allow for sorting when the user clicks on the column headers. However, when the user clicks on a header for a column that

Answer 1

DefaultTableModel returns a column class of Object. As such all comparisons will be done using toString. This may be unnecessarily expensive. If the column only contains one type of value, such as an Integer, you should override getColumnClass and return the appropriate Class. This will dramatically increase the performance of this class.

In this case you should add the snippet code below in your table model:

    @Override
public Class getColumnClass(int columnIndex) {
    if (db.isEmpty()) {
        return Object.class;
    }
    return getValueAt(0, columnIndex).getClass();
}