Why Java Encoder and Decoder Not Working Correctly

How to properly encode strings in java? I'm trying to encode the letter Ü in utf-8 and I'm getting garbage results - d093d19a instead of C39C. What could be the problem?

package org.example;

import java.io.*;
import java.nio.charset.StandardCharsets;
import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Hex;

public class Main {
    public static String convertStringToHex(String str) {
        char[] chars = Hex.encodeHex(str.getBytes(StandardCharsets.UTF_8));

        return String.valueOf(chars);
    }

    public static String convertHexToString(String hex) {

        String result = "";
        try {
            byte[] bytes = Hex.decodeHex(hex);
            result = new String(bytes, StandardCharsets.UTF_8);
        } catch (DecoderException e) {
            throw new IllegalArgumentException("Invalid Hex format!");
        }
        return result;
    }

    public static void main(String[] args) throws IOException {
        System.out.println("encoder Ü: " + convertStringToHex("Ü"));
        System.out.println("decoder Ü error: " + convertHexToString("d093d19a"));
        System.out.println("decoder Ü: " + convertHexToString("C39C"));
    }
}

Output:
encoder Ü: d093d19a
decoder Ü error: Ü
decoder Ü: ?

I work in windows. I know that windows uses its own encoding, can this affect the final result?