AppEngine Java Standard: some of my java17 app instances running jetty-12 instead of jetty-9

[miztaka]

I have a webapp running on AppEngine Standard java17 legacy bundle. I recently noticed that some of it's instances are running jetty-12 instead of jetty-9 and this instance causes a problem on my app. (RequestDispatcher throws Exception)

According to the document, java17 should run jetty-9 but why are some instances running jetty-12?

Thanks

Mitsu

[ronnelg]

Hi @miztaka, 

It must be your old App Engine deployments or configuration might still be using the Jetty 9 or some libraries or dependencies in your application may have compatibility issues with the Jetty 12 so it led to a fallback to Jetty 9. Also, App Engine sometimes caches configurations. It is possible that the Jetty 9 configuration is cached and being used despite the updates.

What I recommend is to double check your App Engine configuration and look for a specified Jetty 9 version and remove it. Make sure all of your project's dependencies are compatible with Java 17 and Jetty 12. Update any outdated libraries that might be causing conflicts. After making any changes to your configuration or dependencies, redeploy your application to App Engine. 

If you are still encountering the same issue, consider creating a new App Engine project and deploying your application to it. This can help rule out any project-specific configuration issues.

Was this helpful? If so, please accept this answer as “Solution”. If you need additional assistance, reply here within 2 business days and I’ll be happy to help.

[miztaka]

Hi @ronnelg ,

in my understandings you are not able to specify jetty version in your AppEngine configuration.
My app is configured to run as java17 runtime and java17 runtime should run jetty-9.4.

Please let me know if there is a way to configure jetty version in my AppEngine Standard app.

Thanks
Mitsu

[joolsbrm]

I had the same issue, and managed to fix it by manually specifying the jetty version to v9 as documented here: https://github.com/GoogleCloudPlatform/appengine-java-standard/blob/main/TRYLATESTBITSINPROD.md

However some instances still try to startup with jetty-12, but now it will shutdown the instance and startup a new one, rather than what it did before which was to register the Servlets, but fail to register any of the endpoints under the Spring Dispatcher Servlet

[miztaka]

Thanks for your comment, this solution looks interesting. I haven't tested this solution but the error has gone despite I still see jetty-12 running occasionally. I believe Google fixed something.