J2SE Version (please include all output from java -version flag):
java version "1.6.0-rc"
Java(TM) SE Runtime Environment (build 1.6.0-rc-b96)
Java HotSpot(TM) Client VM (build 1.6.0-rc-b96, mixed mode, sharing)

Does this problem occur on J2SE 1.4.x or 5.0.x ? Yes / No (pick one)
Yes

Operating System Configuration Information (be specific):
Microsoft Windows 2000 [Version 5.00.2195]

ListSelectionEvent can have indexes less than 0

1) Run the code below
2) Select a row in the table
3) Press the button
4) Observe in the console that the ListSelectionEvent have firstIndex = -1

According to the ListSelectionEvent JavaDoc the indexes should represent the range of rows where the selection might have changed, where 0 is the first row. It should note that the firstIndex can be less than 0.

import static java.awt.BorderLayout.*;
import static java.lang.System.*;
import static javax.swing.JFrame.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.table.*;

public class Test {
  public static void main(String[] args) {
    JFrame frame = new JFrame();
    final JTable table = new JTable(3, 3) {
      public void valueChanged(ListSelectionEvent anEvent) {
        out.println(anEvent);
        super.valueChanged(anEvent);
      }
    };
    frame.add(new JScrollPane(table));
    frame.add(new JButton(new AbstractAction("Fire Table Data Changed") {
      public void actionPerformed(ActionEvent anEvent) {
        ((DefaultTableModel)table.getModel()).fireTableDataChanged();
      }
    }), SOUTH);
    frame.pack();
    frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
    frame.setVisible(true);
  }
}