According to the release notes of the latest Java for Mac OS X update, Apple is now depreciating their port of the JVM.

Java for Mac OS X 10.6 update 3 and 10.5 update 8 release notes

As of the release of Java for Mac OS X 10.6 Update 3, the version of Java that is ported by Apple, and that ships with Mac OS X, is deprecated.

This means that the Apple-produced runtime will not be maintained at the same level, and may be removed from future versions of Mac OS X. The Java runtime shipping in Mac OS X 10.6 Snow Leopard, and Mac OS X 10.5 Leopard, will continue to be supported and maintained through the standard support cycles of those products.

Apple's port is the officially recommended one .

Does anybody know of alternate ports of the JVM?

My reading of the above suggests that Mac OS X 10.7 (coming out next summer) won't be guaranteed to ship with a JVM and we can't depend on the old port of the JVM to run on it.

Does this spell gloom and doom for ScriptMaster on the Mac in 10.7 and beyond?

Tough to know for sure at this point. I'd say it's pretty unlikely that a version of OS X would ship without some option for supporting Java code, either a deprecated JVM from apple, or a supported one from Oracle.

There has been some further news regarding the future of Java on Mac OSX.

http://www.apple.com/pr/library/2010/11/12openjdk.html

From this press release it sounds like Apple will be contributing much of its expertise from its history of porting Java to the Mac so that others (at Oracle it seems) can do the port without starting from scratch.

The ball is now in Oracle's court to actually follow through.