This came up last week, and is something that I need to keep an eye on.
These are some of the commands that one can/should use to monitor ulimit use on a Linux box: -
ps -eLf
ps -eTf
ps -Tp `pidof java`
top -H -p `pidof java`
pstree -p `pidof java`
for pid in $(pgrep java); do ls /proc/$pid/fd | wc -l; done
ps -eTf
ps -Tp `pidof java`
top -H -p `pidof java`
pstree -p `pidof java`
for pid in $(pgrep java); do ls /proc/$pid/fd | wc -l; done