Yes you are right. But as a Java developer I know and I care about the terms JRE and JDK that are used officially and on Windows and many Linux systems and Mac

Yes you are right. But as a Java developer I know and I care about the terms JRE and JDK that are used officially and on Windows and many Linux systems and MacOS. I was not aware of the Fedora package conventions. And as I already wrote, I had most likely installed jdk-devel because, I guess, it is listed in yum and DNF-dragora. Maybe it was a bug in some Fedora related package tool. DNF-dragora had double entries for Java. Unfortunately I do not remember anymore the details. Someone replied this to me: "This is a fairly trivial problem to work around, although maybe this should be one of those "sane default" kind of things. Set the environment variable JAVA_HOME=/etc/alternatives/jre or point it at the specific OpenJDK version you want. That's what /etc/alternatives is for." I guess that is way I tried "alternatives --config java" at the time.