/*

package tree;

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import javax.swing.tree.TreeNode;



 
import java.util.*;
 
public class TreePrint {
 
    public static void main(String[] args) {
 
        Tree<String> root = new Tree<>("RootFolder");
        
        //как здесь к root добавить video. music picture
        // и чтоьы потомки могли пускать узлы до бесконечности
        
        
 
        
 
        
       
        
        
        
       
       
        
        //rootFolder.addChildren(video, music, picture);
        
 
        printCatalog(tree);
 
    }
 
    private static <T> void printCatalog(Tree<T> rootFolder) {
 
        printNode(rootFolder.getRoot());
        ArrayList<Node<T>> kids = tree.iterate();
        printTree(kids);
 
    }
 
    private static <T> void printTree(List<Node<T>> kids) {
        if (kids.isEmpty()) {
            return;
        }
        for (Node<T> kid : kids) {
            printNode(kid);
            printTree(kid.getChildren());
        }
 
    }
 
    private static <T> void printNode(Node<T> kid) {
        System.out.println(kid.getData());
 
    }
}

import java.util.ArrayList;
import java.util.List;

class Tree<T> {
 
    private Node<T> root = null;
 
    private ArrayList<Node<T>> children = new ArrayList<>(); 
 
    public Tree(T data) {
        root = new Node(data);
    }
 
    public Node getRoot() {
        return root;
    }

import java.util.ArrayList;

import java.util.List;



    public class Node<T> {
 
    private T data = null;
    private List<Node<T>> children = new ArrayList<>();
    private Node parent = null;
 
    public Node(T data) {
        this.data = data;
    }
 
    public Node<T> addChild(T data) {
        Node<T> node = new Node<>(data);
        node.parent = this;
        children.add(node);
        
        return node;
    }
    public List<Node<T>> iterate() {
        return children;
    }
 
 
    public void remove(T data) {
        Node<T> node = new Node<>(data);
        node.parent = this;
        children.remove(node);
    }
 
    public List<Node<T>> getChildren() {
        return children;
    }
 
    public Node getParent() {
        return parent;
    }
 
 
    public T getData() {
        return data;
    }
 
    public void setData(T data) {
        this.data = data;
    }
        
 
}

ArrayList<Node<T>> iterate(){
        ArrayList<Node<T>> res = new ArrayList<>();
        for(Node<T> x: children){
            res.add(x);
        }
        return res;

rootFolder.addChildren(video, music, picture);