Finding hard and soft open file limits from within jvm in linux (ulimit -n and ulimit -Hn)

Question

I have a problem where I need to find out the hard and soft open file limits for the process in linux from within a java/groovy program. When I execute ulimit from the termi

Answer 1

Groovy is setting this limit to maximum in it's start-up scripts.

In startGroovy:160:

# Increase the maximum file descriptors if we can.
if [ "$cygwin" = "false" -a "$darwin" = "false" ] ; then
    MAX_FD_LIMIT=`ulimit -H -n`
    if [ $? -eq 0 ] ; then
        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
            MAX_FD="$MAX_FD_LIMIT"
        fi
        ulimit -n $MAX_FD
        if [ $? -ne 0 ] ; then
            warn "Could not set maximum file descriptor limit: $MAX_FD"
        fi
    else
        warn "Could not query businessSystem maximum file 
              descriptor limit: $MAX_FD_LIMIT"
    fi
fi

---

It turns out jvm is setting this limit by itself. I'm not sure why groovy is changing it too. Try:

java -XX:-MaxFDLimit LinuxInteractor

It will disable this behavior.