@CanIgnoreReturnValue
  @Override
  public KmsClient withDefaultCredentials() throws GeneralSecurityException {
    try {
      GoogleCredentials credentials = GoogleCredentials.getApplicationDefault();
      return withCredentials(credentials);
    } catch (IOException e) {
      throw new GeneralSecurityException("cannot load default credentials", e);
    }
  }
Loads <a href="https://developers.google.com/accounts/docs/application-default-credentials"
default Google Cloud credentials</a>.
java_src/src/main/java/com/google/crypto/tink/integration/gcpkms/GcpKmsClient.java