code: public String getApplicationName() {
      String libraryVersion = getLibraryVersion();
  
      // We have to do the following since underlying layers often do not appreciate User-Agent
      // provided as a normal header and override it or treat setting "application name" as the only
      // way to append something to User-Agent header.
      StringBuilder sb = new StringBuilder();
      String customUserAgentValue = getUserAgent();
      if (customUserAgentValue != null) {
        sb.append(customUserAgentValue).append(' ');
      }
      if (libraryVersion == null) {
        sb.append(getLibraryName());
      } else {
        sb.append(getLibraryName()).append('/').append(libraryVersion);
      }
  
      return sb.toString();
    }
docs: Returns the application's name as a string in the format {@code gcloud-java/[version]},
  optionally prepended with externally supplied User-Agent header value (via setting custom
  header provider).