The XSQL Servlet (see Java XDK home page) is an Oracle technology for generating XML from databases accessed using JDBC. It's therefore not restricted to Oracle databases.
It has a very similar feature set to the ESQL tag library, in that it has a declarative XML syntax for describing how to generate XML from an SQL query. There is a default canonical form for the generated XML document (ROWSET/ROW elements) which can be automatically converted by associating a stylesheet with the XSQL page.
The servlet also allows caching of stylesheets, etc.
It's not as flexible as Cocoon, but developers already familiar with this technology should find the migration fairly straight-forward.
See this article from Oracle magazine for examples.