That's what makes JPype detect it's a JDK install and not just the JRE. Also, note that this project is deprecated, you might want to try with the maintained project JPype1 ...

The Java versions in this release of GraalVM community edition are updated and based on OpenJDK 1.8.0_282 and OpenJDK version 11.0.10. The Node.js distribution of GraalVM has been updated to 12.20.1.

I can't open the Fabric Installer .exe as it tells me 'This application requires a Java Runtime Environment 1.8.0' despite being able to run the .jar version perfectly fine.

With the latest release of the JDK, Oracle has embarked upon a new Java versioning scheme. There has always been a disconnect between the branding of the Java product and the version of the underlying ...