In the very same post where Google announced Java 8 being generally available on GAE standard [1], they also stated Java 9 support was already in the works. Of

In the very same post where Google announced Java 8 being generally available on GAE standard [1], they also stated Java 9 support was already in the works. Of course, actual timelines are not publicly known yet, but I wouldn't bet my money they'll take another 3 years to get this ready. [1] https://cloudplatform.googleblog.com/2017/09/Java-8-on-App-Engine-Standard-environment-is-now-generally-available.html https://cloudplatform.googleblog.com/2017/09/Java-8-on-App-E...