Recursive tree walk

import java.util.ArrayList;

public class Main {

    public static void main(String[] args) {
        Main main = new Main();
        main.start();
    }

    static class Node {

        public Node(String name) {
            this.name = name;
        }

        String name;
        ArrayList<Node> children = new ArrayList<>();

    }


    void start() {
        // Create an example tree of nodes:
        Node root = new Node("Root");

        Node root_child1 = new Node("Root child 1");
        root.children.add(root_child1);
        Node root_child2 = new Node("Root child 2");
        root.children.add(root_child2);


        Node parent = new Node("Parent");
        root.children.add(parent);

        Node parent_child1 = new Node("Parent child1");
        parent.children.add(parent_child1);

        Node parent_child2 = new Node("Parent child2");
        parent.children.add(parent_child2);


        // Print the tree:
        this.printNode(root);
    }


    void printNode(Node node) {
        System.out.println(node.name);
        for (Node child_node : node.children) {
            printNode(child_node);
        }
    }
}


Output:
Root
Root child 1
Root child 2
Parent
Parent child1
Parent child2