Run the below test case. It pops a JOptionPane confirm dialog. Using Tab key select
2nd or 3rd button, returned value from showConfirmDialog is always 0.

//begin test case

import javax.swing.*;

public class OptionPaneBug
{
public static void main (String [] args)
{
  int i =
       JOptionPane.showConfirmDialog (null,
        "Press Tab to select different option, then press Enter key. ");

  System.out.println ("Selected value : " + i);
}
}
// end test case