Even the first-generation runtimes no longer use this mechanism. Note https://cloud.google.com/appengine/docs/standard/java/migrating-to-java8#taking_full_advan

Even the first-generation runtimes no longer use this mechanism. Note https://cloud.google.com/appengine/docs/standard/java/migrating-to-java8#taking_full_advantage_of_java_8_runtime_features https://cloud.google.com/appengine/docs/standard/java/migrat...: "All standard Java classes are now available, and there is no class allowlist."