I have launched a project which was currently running in jdk 17.0.3, in the new jdk 18.0.1.1 and got the following error:
Fehler: Beim Laden der Klasse launching.Main ist ein LinkageError aufgetreten
java.lang.UnsupportedClassVersionError: launching/Main (class file version 61.65535) was compiled with preview features that are unsupported. This version of the Java Runtime only recognizes preview features for class file version 62.65535
I have tried cleaning and rebuilding, and the preview features are also enabled for the new version. (Both in the vm args and the .settings-file). Playing around with the jre-settings hasn't helped, and I'm afraid to break something.
Installing the newest version of eclipse did the thing, as the old one wasn't supporting jdk18.