Currently its Oracle only. Well we can use the work that was done here at OACS for the data model in Postgres. Convert the PDL files to use Postgres. Too much work to do. Unless you are in the same boat as I am wherein I have to use CCM 5.0 try to look at OACS 4.5 which has both Postgres and Oracle. If you really need java try Jahia, mmbase or cofax. Jahia is semi opensource but it has a lot ACS stuff.
My initial findings with CCM 5.0 is that is a lot slower than 4.6 or 4.7. Real slow as in http://localhost:8080 will take atleast a second to load.
Red Hat may port CCM to postgres since after all RH database is Postgres.
