Access Gateway was upgraded from R12.8.2 to R12.8.7 and started to crash frequently.
Release : 12.8.07
The packaged core has provided following stack.
(gdb) #0 0x00007fe6c581d387 in raise () from /lib64/libc.so.6
So the jvm was trying to lookup hostname by address and that is where it crashed. Nothing to do with Access Gateway code.
The query is handled by the OS by /lib64/libnss_myhostname.so file and then the java crashed.
One possibility is selinux blocking the libnss and your system administrator should review the selinux logs.
/var/log/audit/audit.log (when auditd is enabled)
/var/log/messages (when auditd is not enabled)
Another way would be to prevent this libnss calls.
Sysadmin can review the nsswitch.conf and see if myhostname is enabled and that can be removed to test if that prevents this libnss calls.