i apologize if my answer is not the most authoritative, because i'm not a jboss CMP developer, but my understanding is that this kind of class can create or is responsible for creating primary keys for entities. i personally use a standard one for mysql which helps with auto_increment tables (generating sequential integer keys), and the one you refer to appears to be for oracle and for the same purpose.
this kind of thing is certainly a standard part of jboss since in the standard jbosscmp-jdbc.xml file there is a set of xml elements called 'entity-commands' that describe implementations of such. you'll certainly find yours listed in there too. i don't know if its a perfectly standard feature of j2ee, however, but at least i haven't come across it in that context explictly --- which doesn't necessarily mean its not compatible.
this stuff is in the for-pay-docs, specifically, JBossBook_321.pdf, and perhaps others as well.
OK I got it. Turns out my wacky consultant probably felt like writing a non-standard, undocumented, jboss extension that replaced something JBoss already provided, and that probably won't work anymore when the next JBoss release comes out. But at least I found the source!
i rather believe it will be stable for quite some time, since (1) the jboss interface his class probably implements will not likely change anytime soon, and if it does, it would most likely remain backwards compatible (potentially requiring a recompile in that case), and (2) the same reassurances can be made for your oracle database, in terms of the sql being used. so i rather think that if your consultant's customization works now, you're in pretty good shape going forward too! mike