Use commons-codec instead of jaxb-api

This is needed to remove the dependency from javax.xml.bind

Author: jeandersonbc

src/main/java/com/adyen/util/HMACValidator.java

@@ -14,7 +14,7 @@
  *
  * Adyen Java API Library
  *
- * Copyright (c) 2017 Adyen B.V.
+ * Copyright (c) 2026 Adyen B.V.
  * This file is open source and available under the MIT license.
  * See the LICENSE file for more info.
  */
@@ -31,8 +31,8 @@
 import java.util.List;
 import javax.crypto.Mac;
 import javax.crypto.spec.SecretKeySpec;
-import javax.xml.bind.DatatypeConverter;
 import org.apache.commons.codec.binary.Base64;
+import org.apache.commons.codec.binary.Hex;
 
 /** Utility class for generating and validating HMAC signatures used in Adyen webhooks. */
 public class HMACValidator {
@@ -61,7 +61,7 @@ public String calculateHMAC(String data, String key)
         throw new IllegalArgumentException("HMAC key is not provided");
       }
 
-      byte[] rawKey = DatatypeConverter.parseHexBinary(key);
+      byte[] rawKey = Hex.decodeHex(key);
       SecretKeySpec signingKey = new SecretKeySpec(rawKey, HMAC_SHA256_ALGORITHM);
 
       Mac mac = Mac.getInstance(HMAC_SHA256_ALGORITHM);

src/test/java/com/adyen/util/HMACValidatorTest.java

@@ -185,4 +185,10 @@ public void testCalculateHMACNullKey() {
       fail();
     }
   }
+  @Test
+  public void testCalculateHMAC() throws SignatureException {
+    var hmac = new HMACValidator();
+    var out = hmac.calculateHMAC("TestPayload", HMAC_KEY);
+    assertEquals("YA9/UDjldIO4Gq68X4ATYYoEaPYH4f4k2uzBBzEF1PA=", out);
+  }
 }