Thank you Greg et al: Well, most people would not want to deal with those are the kinds of complex issues. No wonder all you find online are all kinds of problems while trying to do such things.
The romantic, silly side of me still thinks that probably using the JVM you could find a way to hack into the complexity of that problem. JVM handles all kinds of properties $ java -XshowSettings:properties -version and it can start (actually take over) processes which would then inherit those JVM "Properties". Those java.util.Properties which you can "get" as well as "set" on the command prompt (before the JVM starts): https://docs.oracle.com/en/java/javase/13/docs/api/java.base/java/util/Properties.html https://docs.oracle.com/en/java/javase/13/docs/api/java.base/java/lang/System.html 1) on the command prompt start a java process with settings you would manage 2) then the java code starts via a native process whatever program you need (firefox, libreoffice, ...) I know. It sounds too good to be true ;-) There are all kinds of not totally hopeless attempts at trying to make the JVM and X11 dance well together: https://stackoverflow.com/questions/tagged/java%2bx11?tab=Votes I will let you know how far I could get away with that sort of hack Some of you may have some more, other tips in additions to the ones you have provided me with already. Thank you, lbrtchx