Vaadin 14 app compiled with JDK11 yields blank page, work with JDK8

I’m trying to migrate a Vaadin 14 + Spring Boot application from Java 8 to 11. The application runs fine under Java 11 when compiled under JDK 8. However, when I compile the same application under Java 11 I only get a blank page. There are no errors or exceptions in the log. Hitting the reload button on the browser briefly shows Vaadin’s ‘busy’ bar at the top of the view.

Hi Marcus,

That sounds quite weird. Any chance you youd share an example project where this could be reproduced?

Cheers,
matti

Hi Matti,

attached is a stripped down and slightly obfuscated version of my project which still shows the behaviour.
I played a little with different configurations. The application breaks as soon as the compiler generates class files >1.8. I tried both flavours of OpenJDK 11 (hotspot and openj9) and also Oracle JDK 13. I can build a working version with JDK >= 11 when I set both source and target compliance to 1.8. This smells a little of something which is manipulating the bytecode directly and can’t quite understand class files > 1.8…
I agree, this is really weird.

The main module is vaadin-poc-main. When you open https://localhost:8443 you should see a login screen.

Cheers,

Marcus
18186533.zip (185 KB)