How to make ganttproject use of local-only JRE

I did not got, how to make ganttprojekt to use a locally only installed JRE:
W10/64 with JPortable/openJKD-portable with no system-wide java_home
I see the starting-script but did not find the place to fill the full path to the java.exe.
Any advice is welcome.

I am not sure that I completely understand what is “locally only installed JRE” but anyway, if we’re talking about Windows and ganttproject.bat, here is a direct link to the place where it sets the full path to java.exe:

If you set JAVA_HOME just above this line, it will launch java.exe from the path specified by JAVA_HOME

Yes, filling in this line
set “JAVA_HOME=c:\portableapps\commonfiles\java”
worked like a charm - thanks