Oracle Database 11.2 linux can't kill external program started by job

I am running Oracle DB 11.2 on RHEL 7. I have tables, procedures, etc. and other things work fine.

I've design a method of starting a java application in the background.

java swing screen calls -> DB procedure which starts external job -> which calls an OS bash script (call it appcontrol) -> which starts a java application.

The java application has a shutdown hook.

If, at the OS command level, I execute the appcontrol script to start the java app and then stop the java app (using SIGTERM and the apps PID), it works fine; shutdown hook gets called, app terminates, no problem.