I've been using PostgreSQL for quite some time now, and it is rock solid.
I don't know about spatial data in PostgreSQL, however. JBoss can be managed over the web using the JMX/HTML interface.
we tried both postgres and oracle for spatial data applications. the advantage of postgres is that it supports geometrical datatypes, where as oracle does a lot of mapping for different coordinate systems which we need to support, so it might depend what your tasks for spatial data are, the jdbc drivers are both stable.