title: Adding new leaf to jTree node
body: <p>Let's say, I have this code of a jTree</p>
  
  <pre><code>    JTree jTree = new JTree() ;
      DefaultMutableTreeNode root = new DefaultMutableTreeNode("root") ;
      jTree.setModel( new DefaultTreeModel(root));
  
      DefaultMutableTreeNode firstNode = new DefaultMutableTreeNode("first node") ;
  </code></pre>
  
  <p>Now I want to add a leaf into the node named "first node" ( which is currently a leaf ) from a place where firstNode variable is not available. How can it be done? </p>
  
  <p>Clearification:
  Okey! I have a JFrame in a class (extends swing) and a jTree is a private member of this class. Now I pass this class object (as a parameter) into another class method where the jTree is supposed to be populated. But I couldn't do anything with that <strong>jTree</strong> from another class method. (Of course accessing private method is not my problem :) </p>