How to use

hexDecode

method

in

org.wildfly.security.util.ByteIterator

@Override
public void handle(Callback[] callbacks) throws IOException, UnsupportedCallbackException {
  for (Callback callback : callbacks) {
    if (callback instanceof PasswordCallback) {
      ((PasswordCallback) callback).setPassword(credential.toCharArray());
    } else if (callback instanceof NameCallback) {
      ((NameCallback) callback).setName(name);
    } else if (callback instanceof RealmCallback) {
      ((RealmCallback) callback).setText(realm);
    } else if (callback instanceof CredentialCallback) {
      CredentialCallback cb = (CredentialCallback) callback;
      Password password;
      switch (cb.getAlgorithm()) {
        case ALGORITHM_CLEAR:
          password = ClearPassword.createRaw(ALGORITHM_CLEAR, credential.toCharArray());
          break;
        case ALGORITHM_DIGEST_MD5:
          byte[] decodedDigest = ByteIterator.ofBytes(credential.getBytes(StandardCharsets.UTF_8)).hexDecode().drain();
          password = DigestPassword.createRaw(ALGORITHM_DIGEST_MD5, name, realm, decodedDigest);
          break;
        default:
          continue;
      }
      cb.setCredential(cb.getCredentialType().cast(new PasswordCredential(password)));
    }
  }
}