code: public static Optional<TypeElement> generatedAnnotation(
        Elements elements, SourceVersion sourceVersion) {
      return Optional.ofNullable(
          elements.getTypeElement(
              sourceVersion.compareTo(SourceVersion.RELEASE_8) > 0
                  ? "javax.annotation.processing.Generated"
                  : "javax.annotation.Generated"));
    }
docs: Returns the element corresponding to the {@code @Generated} annotation present at the target
  {@code SourceVersion}.
  
  <p>Returns {@code javax.annotation.processing.Generated} for JDK 9 and newer, {@code
  javax.annotation.Generated} for earlier releases, and Optional#empty()} if the annotation is
  not available.