Java example to print root, height of a tree and check whether it is balanced or not

import java.util.*;

public class Question4_3 {

    static class Node {
        Integer data;
        Node left;
        Node right;

        public Node(Integer data) {
            this.data = data;
        }

        public int height() {
            int leftHeight = left != null ? left.height() : 0;
            int rightHeight = right != null ? right.height() : 0;
            return 1 + Math.max(leftHeight, rightHeight);
        }

        public boolean isBalanced() {
            int leftHeight = left != null ? left.height() : 0;
            int rightHeight = right != null ? right.height() : 0;
            return (Math.abs(leftHeight - rightHeight) <= 1);
        }
    }

    public static Node minimalBST(int[] sorted) {
        return minimalBST(sorted, 0, sorted.length - 1);
    }

    private static Node minimalBST(int[] sorted, int start, int end) {

        if (start > end) {
            return null;
        }

        int mid = (start + end) / 2;
        
        Node node = new Node(sorted[mid]);

        node.left = minimalBST(sorted, start, mid - 1);
        node.right = minimalBST(sorted, mid + 1, end);

        return node;
    }

    public static Node insert(Node node, Integer data) {
        if (data == null) {
            return null;
        }

        if (node == null) {
            node = new Node(data);
            return node;
        }

        if (data.compareTo(node.data) <= 0) {
            if (node.left == null) {
                node.left = new Node(data);
            } else {
                insert(node.left, data);
            }
        } else {
            if (node.right == null) {
                node.right = new Node(data);
            } else {
                insert(node.right, data);
            }
        }

        return node;
    }

    public static void main(String[] args) {
        int[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};

        Node root = minimalBST(array);

        System.out.println("Root? " + root.data);
        // System.out.println("Created BST? " + root.isBST());
        System.out.println("Height: " + root.height());
        System.out.println("Is balanced? " + root.isBalanced());

        Random random = new Random();

        root = null;
        array = new int[20];

        for (int i = 0; i < array.length; i++)
        {
            array[i] = random.nextInt(array.length);
            root = insert(root, array[i]);
            System.out.print(array[i] + " ");
        }
        System.out.println();

        // root = minimalBST(array);

        System.out.println("Root? " + root.data);
        System.out.println("Height: " + root.height());
        System.out.println("Is balanced? " + root.isBalanced());
    }
}