HmacSHA256 Signature in Java

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

import static java.nio.charset.StandardCharsets.UTF_8;

public class HmacUtils {

    String generateHmac256(String message, byte[] key) throws InvalidKeyException, NoSuchAlgorithmException {
        byte[] bytes = hmac("HmacSHA256", key, message.getBytes());
        return bytesToHex(bytes);   (1)
    }

    byte[] hmac(String algorithm, byte[] key, byte[] message) throws NoSuchAlgorithmException, InvalidKeyException {
        Mac mac = Mac.getInstance(algorithm);
        mac.init(new SecretKeySpec(key, algorithm));
        return mac.doFinal(message);
    }

    String bytesToHex(byte[] bytes) {   (2)
        final char[] hexArray = "0123456789abcdef".toCharArray();
        char[] hexChars = new char[bytes.length * 2];
        for (int j = 0, v; j < bytes.length; j++) {
            v = bytes[j] & 0xFF;
            hexChars[j * 2] = hexArray[v >>> 4];
            hexChars[j * 2 + 1] = hexArray[v & 0x0F];
        }
        return new String(hexChars);
    }

     public static void main(String[] args) throws NoSuchAlgorithmException, InvalidKeyException {
        String valueToDigest = "The quick brown fox jumps over the lazy dog";
        byte[] key = "secret".getBytes();

        HmacUtils hm = new HmacUtils();
        String messageDigest = hm.generateHmac256(valueToDigest, key);
        System.out.println(messageDigest);
    }
}

dependencies {
// https://mvnrepository.com/artifact/com.google.guava/guava
    compile group: 'com.google.guava', name: 'guava', version: '29.0-jre'
}

import com.google.common.hash.Hashing;

public class HMacTest {

    public void hmac256() {
        String valueToDigest = "The quick brown fox jumps over the lazy dog";
        byte[] key = "secret".getBytes();

        String gHmac = Hashing.hmacSha256(key)
                .newHasher()    (1)
                .putString(valueToDigest, UTF_8)
                .hash()
                .toString();    (2)
        System.out.println(gHmac);
    }
}

dependencies {
    // https://mvnrepository.com/artifact/commons-codec/commons-codec
    compile group: 'commons-codec', name: 'commons-codec', version: '1.14'
}

import org.apache.commons.codec.digest.HmacAlgorithms;
import org.apache.commons.codec.digest.HmacUtils;

public class HMacTest {

    public void hmac256() {
        String valueToDigest = "The quick brown fox jumps over the lazy dog";
        byte[] key = "secret".getBytes();

        HmacUtils hm256 = new HmacUtils(HmacAlgorithms.HMAC_SHA_256, key);
        //hm256 object can be used again and again
        String hmac = hm256.hmacHex(valueToDigest);
        System.out.println(hmac);
    }
}

 String hexPom = hm256.hmacHex(new File("pom.xml"));