When you say, shutdown, does the JVM crash or is it a clean shutdown? Can you attach the server.log? Do you see any JVM dump files generated (the location of which depends on how the server was started, but looking in JBOSS_HOME/bin folder might be a good start). There was also a good suggestion in this other thread on a way to figure out what triggered the process to be killed Re: Wildfly 8.2 process go down without any logs NEW MESSAGES, see if that helps narrow down the issue.
Thank you so much.
It has been a nuisance of ours for several months now and we finally diagnosed and handled the problem.
Nothing was written to the server.log in standalone/log and neither to the console.log in /var/log/wildfly.
The thread you linked to however was perfect.
dmesg | egrep -i -B100 'killed process'
By using this command we could see what processes the system has killed, and Java was among them.
It killed Java due to running out of memory.
So we followed a guide to add a swapfile - we added one of 2GB and the problem disappeared.
Before it was present at every single redeployment, now for two consecutive pushes, there has been no problem.