I'm still receiving this error with the headless version when executing songkong.sh:
You have attempted to start in GUI mode but your environment does not support using the GUI
I changed my memory allocation settings as follows for songkongremote.sh:
jre64/bin/java -Xms1024m -Xmx4096m -jar lib/songkong-5.8.jar -r
..and the job completed but I wouldn't say successfully as it did not appear to read *any* of the files. Since I'm no longer receiving OOM errors, should I open the processing issue in another thread (which appears to be database related after looking at the debug logs a bit more closely)?
EDIT: Deleting the database manually (not from the web UI, that simply hung), fixed the issue. Songs are matching.