How to implement a tree data-structure in Java?

Question

Is there any standard Java library class to represent a tree in Java?

Specifically I need to represent the following:

• The sub-tree at any node can have

Answer 1

public abstract class Node {
  List children;

  public List getChidren() {
    if (children == null) {
      children = new ArrayList<>();
    }
    return chidren;
  }
}

As simple as it gets and very easy to use. To use it, extend it:

public class MenuItem extends Node {
  String label;
  String href;
  ...
}