Navie level questions

1. Binary Tree Maximum Node

Find the maximum node in a binary tree,return the node.

public class MaximumNode{
      public TreeNode maxNode(TreeNode root){
                 if(root == null) return root;
                 TreeNode left = maxNode(root.left);
                 TreeNode right = maxNode(root.right);
                 return max(root,max(left,right));            
      }          
      public TreeNode max(TreeNode node,TreeNode anotherNode){
                 if(node == null) return anotherNode;   
                 if(anotherNode == null) return node;
                 if(node.val > anotherNode.val) return node;
                 return anotherNode;
      } 
}