Link: http://www.xmlmind.com/qizx/
Source Author or Organization: Pixware

- Qizx/db, a fast and lightweight XML database engine natively supporting XQuery - Qizx/db is an embeddable, high-speed, native XML database engine written in Java™, with the querying and processing capabilities of a fully fledged XQuery (W3C XML Query) implementation. - Qizx/db is designed for software developments which require advanced XML querying and processing capabilities. It can be used in servlet-J2EE environment or can be directly embedded in Java applications. - Qizx/db supports main XML standards, works with very voluminous documents as well as very large collections of small documents, performs concurrent updates and queries within ACID transactions, features many built-in extensions and extensibility mechanisms. - Qizx/db aims at being a lightweight and flexible tool offering great power at a quite affordable cost.