Description of problem:


Version-Release number of selected component (if applicable): at least since Fedora 31


How reproducible: always reproducible


Steps to Reproduce:
1. Install any JDK package that's not 8 (and its "-devel" version)
2. Install maven package (which requires JDK 8)
3. Set the "java" and "javac" alternatives to that other JDK
4. Check "mvn -v", see that it still uses JDK 8 forcefully

Actual results:
Maven is executed with JDK 8


Expected results:
Maven is executed with the JDK set using alternatives (reasonably the one of "javac", but maybe should be another alternative alias as its a jdk reference rather than one to the javac binary)


Additional info:
Assuming no JAVA_HOME, no .mavenrc etc, the /usr/bin/mvn script has the following line:

if [ -f /usr/share/java-utils/java-functions ] ; then
  . /usr/share/java-utils/java-functions
  set_jvm
  set_javacmd
fi

And in /usr/share/java-utils/java-functions we have, amongst others:

...
    case "${_prefer_jre}" in
        1|[Yy][Ee][Ss]|[Tt][Rr][Uu][Ee])
            dirs="/usr/lib/jvm/jre-1.8.0-openjdk:/usr/lib/jvm/java-1.8.0-openjdk"
            ;;
        *)
            dirs="/usr/lib/jvm/java-1.8.0-openjdk:/usr/lib/jvm/jre-1.8.0-openjdk"
            ;;
    esac
...

Meaning that assuming no override, we will always use the JDK 8 installed as a dependency of maven, ignoring any user system-wide Java alternative setting.