longest palindrome subsequence(Recursion)

 import java.util.*;

public class LongestPalindromicSequence {

    public static int findLongest(String str) {

        int idx = 0;

        String curr = "";

        ArrayList<String> subsequences = findSubsequence(str, idx, curr);

        int maxLen = 0;

        for (String subsequence : subsequences) {

            if (isPalindrome(subsequence)) {

                maxLen = Math.max(maxLen, subsequence.length());

            }

        }

        return maxLen;

    }

    public static boolean isPalindrome(String subsequence) {

        int n = subsequence.length();

        for (int i = 0; i < n / 2; i++) {

            if (subsequence.charAt(i) != subsequence.charAt(n - i - 1)) {

                return false;

            }

        }

        return true;

    }

    public static ArrayList<String> findSubsequence(String str, int i, String curr) {

        ArrayList<String> subsequence = new ArrayList<>();

        if (i == str.length()) {

            subsequence.add(curr);

            return subsequence;

        }

        subsequence.addAll(findSubsequence(str, i + 1, curr + str.charAt(i)));

        subsequence.addAll(findSubsequence(str, i + 1, curr));

        return subsequence;

    }

    public static void main(String[] args) {

        System.out.println("Enter string:");

        Scanner sc = new Scanner(System.in);

        String str = sc.nextLine();

        System.out.println(findLongest(str));

    }

}