Project Euler 4: largest palindrome

largest_palindrome.java

import java.util.TreeSet;

class Scratch {
    static StringBuilder sb = new StringBuilder();

    public static void main(String[] args) {
        int solution = findLargestPalindrome();
        System.out.println(solution);
    }

    private static int findLargestPalindrome() {
        TreeSet<Integer> possibles = new TreeSet<>();
        for (int i = 999; i >= 100; i--) {
            for (int j = i; j >= 100; j--) {
                if (isPalindrome(i * j)) {
                    possibles.add(i * j);
                    break;
                }
            }
        }
        return possibles.last();
    }

    private static boolean isPalindrome(int i) {
        sb.setLength(0);
        String s = Integer.toString(i);
        // Reusing the same SB is more optimised than creating a new one, takes some load off GC
        String reverse = sb.append(s).reverse().toString();
        return s.equals(reverse);
    }
}