Defines the requirements for an object that can be used as a tree node in a
javax.swing.JTree . This interface add the
getUserObject() to
Swing's interface, which seems to have been forgotten in J2SE.
since: 2.0 version: $Id: TreeNode.java 20883 2006-08-07 13:48:09Z jgarnett $ author: Martin Desruisseaux