Try something like this:
       jListFiles.addMouseListener(new java.awt.event.MouseAdapter() {
        public void mouseClicked(java.awt.event.MouseEvent evt){
         JList list = (JList)evt.getSource();
         if (evt.getClickCount()==2) goButtonClicked(evt);
        }
       });

quoting from the JavaDoc

JList doesn't provide any special support for handling double or
triple (or N) mouse clicks however it's easy to handle them using a
MouseListener. Use the JList method locationToIndex() to determine
what cell was clicked. For example:

final JList list = new JList(dataModel);
MouseListener mouseListener = new MouseAdapter() {
    public void mouseClicked(MouseEvent e) {
        if (e.getClickCount() == 2) {
            int index = list.locationToIndex(e.getPoint());
            System.out.println("Double clicked on Item " + index);
         }
    }
};
list.addMouseListener(mouseListener);