Thank you for responce, seems simple, but you help me a lot.

I had the same error that is quiet generic "can't find pid file".
No journalctl, neither systemctl made the sence.
The key was looking the log of jboss or wildfly in my case (whereever you have it JBOSS_CONSOLE_LOG),
it was very descriptive that the service couldn't find the JAVA_HOME.

Fixing this,I have got the solution