Where are the unchecked errors?

Question

I get the warning
GenericTree.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.Busy coding a generic tree class and was wondering where I did something incorrect. Here's the code so far...
class TreeNode<T extends Comparable>
     TreeNode<T> leftNode;
     T data;
     TreeNode<T> rightNode;
     // contructor initialises data and makes this a leaf node
     public TreeNode(T nodeData)
          data = nodeData;
          leftNode = rightNode = null;
     // locate insertion point & insert node; ignore duplicate values
     public void insert(T insertValue)
          if(data.compareTo(insertValue) < 0)
               if(leftNode == null)
                    leftNode = new TreeNode<T>(insertValue);
               else // continue traversing left subtree
                    leftNode.insert(insertValue);
          else if(data.compareTo(insertValue) > 0)
               if(rightNode == null)
                    rightNode = new TreeNode<T>(insertValue);
               else // continue traversing right subtree
                    rightNode.insert(insertValue);
public class GenericTree<T extends Comparable>
     private TreeNode<T> root;
     // contructor initializes root of a Tree object to null
     public GenericTree()
          root = null;
     public void insertNode(T insertValue)
          if(root == null)
               root = new TreeNode<T>(insertValue); // create new node
          else
               root.insert(insertValue); // calls insert method
}Thanks!

Answer 1

class TreeNode<T extends Comparable>You used a raw type here. Try this instead:class TreeNode<T extends Comparable<T>>