Getting JRuby gem utility to work

I've been cursing my brains out trying to get the JRuby version of gem to work. After much hunting around, I found that a Java memory size issue was causing the problem. Things have been working fine since I started installing gems with:

jruby -J-Xmx512M -S gem install

My apologies for having lost the original reference to this information. This bug entry might have been where I first found the solution.