Two search algorithms for a tree, three implementations

Tree.java

import java.util.ArrayList;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.Set;
import java.util.Stack;

public class Tree {
	
	public List<Node> depthFirstSearchIterative(Node root) {
		List<Node> results = new ArrayList<>();
		Stack<Node> stack = new Stack<Node>();
		Set<Node> visited = new HashSet<>(); 
		
		stack.add(root);
		
		while(!stack.isEmpty()) {
			Node node = stack.pop();
			if (!visited.contains(node)) {
				visited.add(node);
				stack.push(node);
				for (Node child : node.getChildren()) {
					stack.push(child);
				}
			} else {
				results.add(node);
			}
		}
			
		
		return results;
	}
	
	public List<Node> depthFirstSearchRecursive(Node root) {
		List<Node> results = new ArrayList<>();
		
		for (Node child : root.getChildren()) {
			results.addAll(depthFirstSearchRecursive(child));
		}
		results.add(root);
		
		return results;
	}
	
	public List<Node> breadthFirstSearch(Node root) {
		List<Node> results = new ArrayList<>();
		Queue<Node> queue = new LinkedList<Node>();
		
		queue.add(root);
		
		while(!queue.isEmpty()) {
			Node node = queue.remove();
			results.add(node);
			queue.addAll(node.getChildren());
		}
		
		return results;
	}
	
	public static class Node {
		
		private Object value;
		private List<Node> children = new ArrayList<>();
		
		public Node(Object value) {
			this.value = value;
		}
		
		public void addChild(Node child) {
			children.add(child);
		}
		
		public List<Node> getChildren() {
			return children;
		}
		
		@Override
		public String toString() {
			return value.toString();
		}
		
	}

	public static void main(String[] args) {
		Tree tree = new Tree();
		Node root = new Node("home");
		
		Node documents = new Node("documents");
		root.addChild(documents);
		documents.addChild(new Node("tax_return_2015.pdf"));
		documents.addChild(new Node("sales_receipt.pdf"));
		documents.addChild(new Node("christmas_list.txt"));
		
		Node pictures = new Node("pictures");
		root.addChild(pictures);

		Node kids = new Node("kids");
		pictures.addChild(kids);
		kids.addChild(new Node("baby.jpg"));
		kids.addChild(new Node("vacation.jpg"));

		pictures.addChild(new Node("silly.gif"));
		
//		-> home
//		   -> pictures
//		      -> silly.gif
//		      -> kids
//		         -> baby.jpg
//		         -> vacation.jpg
//		   -> documents
//		      -> tax_return_2015.pdf
//		      -> sales_receipt.pdf
//		      -> christmas_list.txt

		System.out.println("DFS iterative : " + tree.depthFirstSearchIterative(root));
		System.out.println("DFS recursive : " + tree.depthFirstSearchRecursive(root));
		System.out.println("BFS iterative : " + tree.breadthFirstSearch(root));
	}
	
}