Find the all Kth ancestor nodes in an N-ary tree

import java.util.Vector;
import java.util.ArrayList;
// Java program for
// Find the all Kth ancestor nodes in an N-ary tree 
class TreeNode
{
	public int key;
	public Vector < TreeNode > child;
	public TreeNode(int key)
	{
		this.key = key;
		this.child = new Vector < TreeNode > ();
	}
	// Add new child
	public void addChild(int key)
	{
		TreeNode t = new TreeNode(key);
		this.child.add(t);
	}
}
public class NAryTree
{
	public TreeNode root;
	public NAryTree()
	{
		// Set initial tree root to null
		this.root = null;
	}
	// Print every Kth ancestor in n-arr tree node
	public void printKthAncestor(ArrayList < Integer > path, 
                                  TreeNode node, int k)
	{
		if (node == null)
		{
			return;
		}
		int i = 0;
		// Add path node
		path.add(node.key);
		// iterating the child of given node
		while (i < node.child.size())
		{
			// Recursively visit child node
			printKthAncestor(path, node.child.get(i), k);
			i++;
		}
		int n = path.size();
		if (n >= k + 1)
		{
			System.out.println(" Node [" + node.key + "] : Ancestor : [" + 
                               path.get((n - k) - 1) + "] ");
		}
		else
		{
			// When kth ancestor not exist
			System.out.println(" Node [" + node.key + "] : Ancestor : [None] ");
		}
		if (path.size() > 0)
		{
			path.remove(path.size() - 1);
		}
	}
	public void everyKthAncestor(int k)
	{
		if (k <= 0)
		{
			return;
		}
		if (this.root == null)
		{
			System.out.print("\n Empty Tree \n");
			return;
		}
		// Use to collect tree path
		ArrayList < Integer > path = new ArrayList < Integer > ();
		// Display given k
		System.out.println(" Given K [" + k + "]");
		// Display Kth ancestor
		printKthAncestor(path, this.root, k);
	}
	public static void main(String[] args)
	{
		NAryTree tree = new NAryTree();
		/*
		           10
		          /   \
		         /     \
		        /       \   
		       8         5
		      /|\      /|\ \ 
		     / | \    / | \ \
		    -2 1  6  7 18 3  4
		      / \           /| \
		     9  11         2 1  3
		       /  \
		      17   12   
		    -----------------------
		    Constructing N-Arr tree
		*/
		// First element of tree
		tree.root = new TreeNode(10);
		tree.root.addChild(8);
		tree.root.addChild(5);
		// Add child node [-2,1,5] in node (8)
		tree.root.child.get(0).addChild(-2);
		tree.root.child.get(0).addChild(1);
		tree.root.child.get(0).addChild(6);
		// Add child node [9,11] in node (1)
		tree.root.child.get(0).child.get(1).addChild(9);
		tree.root.child.get(0).child.get(1).addChild(11);
		// Add child node [17  12] in node (11)
		tree.root.child.get(0).child.get(1).child.get(1).addChild(17);
		tree.root.child.get(0).child.get(1).child.get(1).addChild(12);
		// Add child node [7 18 3  4] in node (5)
		tree.root.child.get(1).addChild(7);
		tree.root.child.get(1).addChild(18);
		tree.root.child.get(1).addChild(3);
		tree.root.child.get(1).addChild(4);
		// Add child node [2,1,3] in node (7)
		tree.root.child.get(1).child.get(3).addChild(2);
		tree.root.child.get(1).child.get(3).addChild(1);
		tree.root.child.get(1).child.get(3).addChild(3);
		tree.everyKthAncestor(2);
	}
}

input

 Given K [2]
 Node [-2] : Ancestor : [10]
 Node [9] : Ancestor : [8]
 Node [17] : Ancestor : [1]
 Node [12] : Ancestor : [1]
 Node [11] : Ancestor : [8]
 Node [1] : Ancestor : [10]
 Node [6] : Ancestor : [10]
 Node [8] : Ancestor : [None]
 Node [7] : Ancestor : [10]
 Node [18] : Ancestor : [10]
 Node [3] : Ancestor : [10]
 Node [2] : Ancestor : [5]
 Node [1] : Ancestor : [5]
 Node [3] : Ancestor : [5]
 Node [4] : Ancestor : [10]
 Node [5] : Ancestor : [None]
 Node [10] : Ancestor : [None]