Hackerrank - A Very Simple Multiple

import java.math.BigDecimal;
        import java.util.ArrayList;
        import java.util.List;
        import java.util.Scanner;
        import java.util.regex.Pattern;

// https://www.hackerrank.com/challenges/a-very-special-multiple
public class AVerySpecialMultiple {

    private static Pattern PATTERN = Pattern.compile("^(4+)(0*)$");

    private static final String test1 = "3\n" +
            "4\n" +
            "5\n" +
            "80";
    private static final String test2 = "5\n" +
            "62\n" +
            "67\n" +
            "20\n" +
            "63\n" +
            "81";
    private static final String test3 = "8\n" +
            "4\n" +
            "5\n" +
            "80\n" +
            "62\n" +
            "67\n" +
            "20\n" +
            "63\n" +
            "81";

    public static void main(String[] args) {


//        try (Scanner sc = new Scanner(System.in)) {
        try (Scanner sc = new Scanner(test3)) {
            int t = sc.nextInt();
            while (t-- > 0) {
                long X = sc.nextLong();
                BigDecimal x = new BigDecimal(X);
                BigDecimal y = geraNumeros(x);
                if (y == null) {
                    System.out.println("Illegal value for X");
                    continue;
                }
                BigDecimal multi = x.multiply(y);
                int a = multi.toString().replaceAll("0", "").length();
                int b = multi.toString().replaceAll("4", "").length();
                int _2timesAplusB = (2 * a) + b;
                System.out.printf("X [%s] * Y [%s] = MULTI [%s] (0s: %d, 4s: %d) | (2 * a) + b = %d\n", x.toString(), y.toString(), multi.toString(), a, b, _2timesAplusB);
                //System.out.println(_2timesAplusB);
            }
        }
    }

    private static BigDecimal geraNumeros(BigDecimal x) {
        List<BigDecimal> numeros = new ArrayList<>();
        BigDecimal FOUR = new BigDecimal(4);
        if (check(x, FOUR)) {
            return FOUR.divide(x, BigDecimal.ROUND_HALF_EVEN);
        }
        numeros.add(FOUR);

        int i = 0, j = 0;
        while (i < Integer.MAX_VALUE) {
            BigDecimal result = numeros.get(j++).multiply(BigDecimal.TEN);
            if (check(x, result)) {
                return result.divide(x, BigDecimal.ROUND_HALF_EVEN);
            }
            numeros.add(result);
            i++;

            result = result.add(FOUR);
            if (matches(result)) {
                if (check(x, result)) {
                    return result.divide(x, BigDecimal.ROUND_HALF_EVEN);
                }
                numeros.add(result);
                i++;
            }
        }

        return null;
    }

    private static boolean check(BigDecimal x, BigDecimal result) {
        return result.remainder(x).equals(BigDecimal.ZERO);
    }

    private static boolean matches(BigDecimal multi) {
        return PATTERN.matcher(multi.toString()).matches();
    }
}