@Override
  public boolean equals(Object obj) {
    if (!(obj instanceof TranslateOptions)) {
      return false;
    }
    TranslateOptions options = (TranslateOptions) obj;
    return baseEquals(options)
        && Objects.equals(apiKey, options.apiKey)
        && Objects.equals(targetLanguage, options.targetLanguage);
  }
Returns the code for the default target language.
java-translate/google-cloud-translate/src/main/java/com/google/cloud/translate/TranslateOptions.java