kept snapshot of the reccurence of the dreaded '<type> already defined' problem which likely points to a but in xjc (shown here in its full complexity)
managed to narrow-down the resurgent '<type> already defined' problem, enough to make an SO post and a JAXB JIRA issue
managed to find a work-around to the resurgent '<type> already defined problem' by making all schemaLocations local so no catalog is used