How to trace why Jboss app down sudden

Question

Good day,

I have an application deployed in Jboss I found that my web application keep down without any error log in my sever log or application log.

I go to check the /var/log/messages log, and found something as follow:

Oct 16 08:30:04 wmdvvmyap02 kernel: Out of memory: Kill process 23962 (java) score 136 or sacrifice child
Oct 16 08:30:04 wmdvvmyap02 kernel: Killed process 23962 (java) total-vm:4537032kB, anon-rss:2220360kB, file-rss:0kB, shmem-rss:0kB

And I have enable top log by following command before this:

top -b -n2000 -d600 >> top.out &

At the same timestamp in the top.out log, I can see the PID 23962 still exist at 8:26am, however, its gone at 8:36am. During 8:26am, so far I didnt see there is a memory spike, the available memory still having 2GB:

top - 08:26:22 up 144 days, 17:42,  0 users,  load average: 0.20, 0.19, 0.16
Tasks: 239 total,   1 running, 238 sleeping,   0 stopped,   0 zombie
%Cpu(s):  1.5 us,  0.6 sy,  0.0 ni, 97.9 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
KiB Mem : 16267268 total,  2302560 free, 12221056 used,  1743652 buff/cache
KiB Swap:        0 total,        0 free,        0 used.  2833032 avail Mem 

And I also have enable SAR log, but so far I didnt see anything related in the SAR log, so I didnt post the SAR log here.

Other than this, I cant get any clue, and not idea how to continue to troubleshoot to know the root cause.

Kindly advise.