public void clearSelection() Clears the selection; after calling this method, isSelectionEmpty will return true. This is a cover method that delegates to the method of the same name on the list's selection model. See Also: ListSelectionModel.clearSelection(), isSelectionEmpty()
http://java.sun.com/javase/7/docs/api/javax/swing/JList.html#isSelectedIndex%28int%29</code>
J'espère que ca répond à ta question.
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