JDK 6: Generics: List.add() question - keep getting unchecked call warning.

Question

JDK 6
Generics
private TreeNode transactionTreeData;
transactionTreeData.getChildren().add(moduleData);1. transactionTreeData is a TreeNode.
2. the method getChildren() returns a java.util.List
3. the method add() is from the Collection interface.
I keep returning the warning message:
"unchecked call to add(E) as a member of the raw type java.util.List"
I understand what this means, but I am having problems rewriting these lines correctly to remove the warning.
I've tried:
private TreeNode transactionTreeData;
List<TreeNode> treeList = transactionTreeData.getChildren();
treeList.add(moduleData);But I keep returning the same warning message. I guess what is throwing me off is how to I properly add the generic statements when the List is return from a method (getChilden in this example)?
Thanks,
--Todd                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   

Answer 1

This is actually JSF - MyFaces Tomahawk to be exact, my mistake for not adding that in my original thread.
I am dealing with the compiled class:
package org.apache.myfaces.custom.tree2;
public interface TreeNode extends java.io.Serializable {  
     java.util.List getChildren();
}TreeNode.getChildren return a raw List as you can see, no doubt...
Thanks,
--Todd