There are a few differences between Linux and Solaris, such as where to find logfiles, but in general you could take the Linux initscripts and port them to Solaris fairly easily. I think that there's actually an initscript included in the bin directory of
JBoss.
Initscripts still work under the latest versions of Solaris, although for maximum effectiveness, it's good to plug into the "srv" subsystem, which is intended to replace the old init system. The main difference is that srv config files specify prerequisite services, so that, for example, JBoss won't attempt to start if the network didn't init properly.