That's I discovered recently. I admit that my Eclipse is a little it outdated. Hopefully, this is a well known bug and you can easily install an official Eclipse extention just like this :
http://download.eclipse.org/eclipse/updates/4.9-P-builds
Enjoy :)
- Open Help Menu -> Install new software.
- Add the following URL and you shoud seed a plugin to enable jdk 11 support.
http://download.eclipse.org/eclipse/updates/4.9-P-builds
Enjoy :)