Oracle XML Developer's Kit (XDK) is a collection of utilities for manipulating XML in Oracle databases.
The XDK is a set of libraries, components, and utilities which allow developers to communicate with the Oracle database using XML. Developer's can build and deploy C, C++, and Java software programs that process XML. It also works with and supports the Oracle XML DB, which is a set of technologies used for storage and processing of XML in the database. The standards-based XML functionality includes an XML parser, an XSLT processor, an XML class generator, XML SQL Utility, JavaBeans, and XSQL Servlet. (source)