Happy Palindrome Day 02022020

Palindrome.java

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.Stack;

public class Palindrome {

    public static void main(String[] args) {

        LocalDate today = LocalDate.now();
        String formattedDate = today.format(DateTimeFormatter.ofPattern("ddMMyyyy"));
        System.out.println(formattedDate);

        Palindrome p = new Palindrome();
        p.checkPalindrome(formattedDate);

    }

    private void checkPalindrome(String formattedDate) {

        ListNode<Character> list = null;
        ListNode<Character> head = null;

        for (Character c : formattedDate.toCharArray()) {
            if (list == null) {
                list = new ListNode<>(c);
                head = list;
            } else {
                list.next = new ListNode<>(c);
                list = list.next;
            }
        }

        System.out.println(isListPalindrome(head) ? "Happy Palindrome Day" : "not a palindrome day");
    }

    boolean isListPalindrome(ListNode<Character> l) {

        Stack<Character> s = new Stack<>();
        ListNode<Character> head = l;

        while (head != null) {
            s.push(head.value);
            head = head.next;
        }

        head = l;

        while (!s.empty() && head != null) {
            if (!s.pop().equals(head.value)) {
                return false;
            }
            head = head.next;
        }

        return true;
    }

    // Singly-linked list
    class ListNode<T> {
        ListNode(T x) {
            value = x;
        }

        T value;
        ListNode<T> next;
    }
}