Which Java: Oracle Java JDK vs OpenJDK?

One can use Oracle JDK or OpenJDK; check a comparison here.

Note there has been some changes in Licenses from Java SE 11. The changes are fairly complex but a good sumary and explanation of impact can be found here

The current guide/documentation has been produced using the Oracle Java SE 8. However, others have reported using it successfully with OpenJDK, which can be downloaded from AdaptOpenJDK. Then, select the OpenJ9 as JVM (using the Hotspot may yield a fatal error).

On the other hand, errors have been reported when using:

  1. OpenJDK 8 with HotSpot VM.
  2. OpenJDK 11.
an API between SWI-Prolog and the Java Virtual Machine - hosted on GitHub