code: public String getProjectId() {
      if (project != null) {
        if (projectId != null) {
          throw new IllegalArgumentException(
              "Configuring <project> and <projectId> is not allowed, please use only <projectId>");
        }
        getLog()
            .warn(
                "Configuring <project> is deprecated,"
                    + " use <projectId> to set your Google Cloud ProjectId");
        return project;
      }
      return projectId;
    }
docs: Return projectId from either projectId or project. Show deprecation message if configured as
  project and throw error if both specified.