Hi,
I have a similar if not the same issue. I've solved it by running
dyn.load(paste0(system2('/usr/libexec/java_home', stdout = TRUE), '/jre/lib/server/libjvm.dylib'))
in every R-script before loading xlsx and rJava with it. Also found this on Stackoverflow.
Now I have to run this every time I load rJava. This is not convenient. Will your solution, chitemerere, also work on my system (latest High Sierra)?
Thanks.