shiro1 Nexus hash cracking password breaking

bla.java

/**
 * shiro1 cracking snippet
 * So apparently hashcat and JtR don't support these kind of specific hashes
 * with salt and iterations so I needed to code my own.
 * It has shit performance, code is probably retarded; I don't do java so I just
 * hacked this to verify a hash I dumped from Sonatype Nexus wasn't in a basic dictionnary.
 * And if you're here you likely can't afford to be picky...
 * Based on this snippet: https://gist.github.com/mdeggies/cdfd22a9cf28b4e909489b877681a209
 *
 * Usage:
 *  javac -classpath /usr/share/java/shiro-core.jar bla.java
 *  java -classpath /usr/share/java/shiro-core.jar:: bla --arg rockyou.txt
 */
import org.apache.shiro.crypto.hash.Sha512Hash;
import java.util.Base64;
import java.util.stream.*;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.charset.StandardCharsets;

public class bla {

    static byte[] salt;
    static int iteration_count;
    static String b64_hash;

    private static boolean hash(String plaintext_password) {
        try {
            String hash = new Sha512Hash(plaintext_password, salt, iteration_count).toBase64();;

            if (hash.equals(b64_hash)) {
                System.out.println("Found match:");
                System.out.println(plaintext_password);
                return true;
            }
        } catch (Exception e) {
            System.out.println(e);
        }
        return false;
    }   

    public static void main(String[] args) {
        String mcf_string = "$shiro1$SHA-512$500000$ctYP52a2Sp2yIjzzlJAuPg==$ctZ4gQtNd7bKI0SWtktRAiP4Xzgk66sabg3pj0pQBmKZmgG7KAXZqAhBJJ3cCTqenfqi4LTgeZnh4waL6oMH+w=="; //test value = "Jenydoby6!"

        String[] mcf = mcf_string.split("\\$");
        iteration_count = Integer.parseInt(mcf[3]);
        String b64_salt = mcf[4];
        b64_hash = mcf[5];
        salt = Base64.getDecoder().decode(b64_salt.getBytes());

        try {
            Stream<String> lines = Files.lines(Paths.get(args[1]), StandardCharsets.ISO_8859_1);
            lines.parallel().filter(bla::hash).count();
        } catch (Exception e) {
            System.out.println(e);
        }
    }   
}