Tree implementation in Java (root, parents and children)

Question

I need to create a tree structure similar as the attached image in Java. I\'ve found some questions related to this one but I haven\'t found a convincing and well explained

Answer 1

In the accepted answer

public Node(T data, Node parent) {
    this.data = data;
    this.parent = parent;
}

should be

public Node(T data, Node parent) {
    this.data = data;
    this.setParent(parent);
}

otherwise the parent does not have the child in its children list