Binary Search Tree Print Kth Element

PrintKthElementBST.java

public class Main
{
  public static void main(String[] args)
  {
    BinaryTree tree = new BinaryTree();
    
    tree.add(5);
    tree.add(4);
    tree.add(6);
    tree.add(3);
    tree.add(7);
    tree.add(2);
    tree.add(8);
    tree.add(1);
    tree.add(9);
    
    tree.printKthElement(7);
    
    
  }
}

public class TreeNode
{
  int data;
  TreeNode left;
  TreeNode right;
  
  public TreeNode(int d){
  	data = d;
    left = null;
    right = null;
  }
  
}

public class IntWrapper{
 int value = 0; 
}

public class BinaryTree
{
  TreeNode root;
  
  public BinaryTree(){
  	root = null;
  }
  
  public boolean add(int newData){
    if (root == null){
      root = new TreeNode(newData);
      return true;
    }
    else{
      TreeNode curr = root;
      while (true){
        if (curr.data == newData){
          return false;
        }
        else if (curr.data > newData){
          if (curr.left == null){
            curr.left = new TreeNode(newData);
            return true;
          }
          else{
            curr = curr.left;
          }
          
          
        }
        else{
          if (curr.right == null){
            curr.right = new TreeNode(newData);
            return true;
          }
          else{
            curr = curr.right;
          }
        }
      }
    }
    
  }
  
  
  public void printKthElement(int k){
    IntWrapper elementCounter = new IntWrapper();
    printKthElementHelper(root, k, elementCounter);
    
  }
  
  public void printKthElementHelper(TreeNode node, int k, IntWrapper counter){
    
    if (node == null)
      return;
   
    
    printKthElementHelper(node.left, k, counter);
    
    counter.value = counter.value + 1;
    
    if (counter.value == k){
      System.out.println("Kth Element: " + node.data);
    }
    
    printKthElementHelper(node.right, k, counter);
    
    
  }
   
}