Decide Whether A Binary Tree Is Balanced

class Node {
    public Node left, right;
    private static int height(Node n) {
        if (n == null) return 0;
        return 1 + Math.max(height(n.left), height(n.right));
    }
    public static boolean isBalanced(Node n) {
        if (n == null) return true;
        if (Math.abs(height(n.left) - height(n.right)) > 1) return false;
        return isBalanced(n.left) && isBalanced(n.right);
    }
}