Urgent, please help. why the ListSelectionListener() called twice?

Question

I had two JList, and every time, I click value in list1, it will call the ListSelectionListener() twice, and when I click on value in List2, it called the list2 actionListener twice also, I don't know why?
Please help.
The part of the code list below:
jList1 = new JList(words1);
JScrollPane scrollPane1 = new JScrollPane(jList1); jList1.setBackground(Color.lightGray);
jList1.setBorder(BorderFactory.createLoweredBevelBorder());
jList1.addListSelectionListener(new javax.swing.event.ListSelectionListener() {
public void valueChanged(ListSelectionEvent e) {
     jList1_valueChanged(e){
/* add Column_Name to the jList2*/
JScrollPane scrollPane2 = new JScrollPane(jList2);
jList2.setBackground(Color.lightGray);
jList2.setBorder(BorderFactory.createLoweredBevelBorder());
jList2.addListSelectionListener(new javax.swing.event.ListSelectionListener() {
public void valueChanged(ListSelectionEvent e) {
jList2_valueChanged(e);
void jList1_valueChanged(ListSelectionEvent evt)
void jList2_valueChanged(ListSelectionEvent evt)
{     }

Answer 1

You can call ListSelectionEvent.getValueIsChanging() to find out if the selection is in progress or if has been finished. You will get an event both when the user starts the selection (presses the button) and when he/she finishes it (lets go of the betton).
/Michael