Handling Selection Events in a Tree Component
This example adds a listener for selection events to a tree component. 

 
 tree.addTreeSelectionListener(
   new TreeSelectionListener() {
     public void valueChanged(TreeSelectionEvent evt) {
         DefaultMutableTreeNode node = 
           (DefaultMutableTreeNode)
             (evt.getPath().getLastPathComponent());
         process(node);
     }
 });