Glassfish Gem: domain directory not writable

I am running the latest Glassfish Gem on the latest JRuby on both
FreeBSD and Mac, and I get this error

java.lang.RuntimeException: the domain directory is not writable.

if I run as a regular user.

However if I run as root, the error goes away.

I would not like to run as root because of security reasons and would
rather have this service be executed as a regular users. Can someone
please suggest what is the cause of this and where I must set my