Sorting JTable programmatically

Works fine for me:

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;

public class TableBasic extends JPanel
{
    public TableBasic()
    {
        String[] columnNames = {"Date", "String", "Integer", "Boolean"};
        Object[][] data =
        {
            {new Date(), "A", Integer.valueOf(1), Boolean.TRUE },
            {new Date(), "B", Integer.valueOf(2), Boolean.FALSE},
            {new Date(), "C", Integer.valueOf(19), Boolean.TRUE },
            {new Date(), "D", Integer.valueOf(4), Boolean.FALSE}
        };

        DefaultTableModel model = new DefaultTableModel(data, columnNames)
        {
            //  Returning the Class of each column will allow different
            //  renderers and editors to be used based on Class

            public Class getColumnClass(int column)
            {
                switch (column)
                {
                    case 0: return Date.class;
                    case 2: return Integer.class;
                    case 3: return Boolean.class;
                }

                return super.getColumnClass(column);
            }
        };


        JTable table = new JTable(model);
        table.setPreferredScrollableViewportSize(table.getPreferredSize());
        table.setAutoCreateRowSorter(true);

        // DefaultRowSorter has the sort() method

        ArrayList<RowSorter.SortKey> list = new ArrayList<>();
        DefaultRowSorter sorter = ((DefaultRowSorter)table.getRowSorter());
        sorter.setSortsOnUpdates(true);
        list.add( new RowSorter.SortKey(2, SortOrder.ASCENDING) );
        sorter.setSortKeys(list);
        sorter.sort();

        JScrollPane scrollPane = new JScrollPane( table );
        add( scrollPane );
    }

    private static void createAndShowGUI()
    {
        JFrame frame = new JFrame("Table Basic");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(new TableBasic());
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocationByPlatform( true );
        frame.setVisible( true );
    }

    public static void main(String[] args) throws Exception
    {
        SwingUtilities.invokeLater( () -> createAndShowGUI() );
    }
}

Next time post your minimal, reproducible example when something doesn’t work.