Martian Software was talking about NailGun way back in January of 2003 when I emailed them asking about it. I received a message today from Marty Lamb:

If you are receiving this, you have expressed an interest at some point
in a notification when NailGun is available.

Well, it's available.

If it's been so long that you don't remember what it is, NailGun is a
client, server, and protocol for running Java programs within a
persistent JVM, eliminating the JVM startup time.  I appreciate your
patience with the project as I have been swamped with other priorities
for some time now.

Although there are no known issues, there is still some work to be
done.  Most importantly, I need to compile Windows and OSX binaries for
the client.  If you can provide any assistance with this I'd be most
grateful.

More information, a quick start manual, javadocs, and downloads are
available from http://www.martiansoftware.com/nailgun.  There's also
information for joining the NailGun mailing list.  The fact that you are
receiving this message does NOT mean you have been added to the list.

This is a one-time mailing.  If it's unwelcome, you have my sincere
apologies.

- Marty

--
Marty Lamb
Martian Software, Inc.
mlamb at martiansoftware dot com

I’m quite excited about NailGun for use in writing trivial command-line Unix scripts in Java. Going to download it and build a Mac OS X binary while I’m at it too.

Update: Runs nicely on my system, now to explore a bit.