Tim Bray has updated the beta of Genx, his pure C library for outputting canonical XML. This version "can now declare any namespace to have an empty prefix ("") so that it is the default namespace when in effect. Also, you can redeclare a namespace from one prefix to another as long as you’re not in the scope of a declaration. (This restriction will be lifted soon). There are new calls genxAddNamespace for explicitly inserting a namespace declaration, and genxUnsetDefaultNamespace for removing the current default. Finally, there is genxGetNamespacePrefix, which is useful for creating QNames-in-content where Genx generated the prefix." Genx is published under the expat license. This is a very liberal, non-viral but GPL-compatible license.
IBM has updated their XML Parser for Java to version 4.3. This release is based on Xerces-J 2.6.2 and supports XML 1.0 and 1.1, Namespace 1.0 and 1.1, W3C XML Schema Recommendation 1.0, SAX 1.0 and 2.0, DOM Level 1, DOM Level 2, XML catalogs, some experimental features of DOM Level 3 Core and Load/Save Working Drafts, JAXP 1.2, and XNI.
Didier Demany has released xmloperator 3.0, an open source, tree-based XML editor written in Java. Editing can be guided by a RELAX NG schema or a DTD. Version 3.0 adds support for editing documents larger than available memory. xmloperator is published under a BSD-like license.